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Subject: Geography

  • Aurora Borealis: What are Northern and Southern lights? Why do they occur?

    Why in the news?

    • In a rare event, the night sky over Hanle village in Ladakh was illuminated by the northern lights or aurora borealis.
      • Concurrently, the southern lights, or aurora australis, were observed in New Zealand and Australia.

    What are Auroras?

    • Auroras are natural light displays that appear as bright, swirling curtains in the night sky.
    • They are typically seen near the Poles but can occasionally be observed at lower latitudes.
    • These lights can display a range of colors, including blue, red, yellow, green, and orange, due to the interaction of solar particles with different gases in the Earth’s atmosphere.
    • The phenomenon is known as:
    1. Aurora borealis in Northern Hemisphere and
    2. Aurora australis in Southern Hemisphere

    What causes Auroras?

    • Interaction with Earth’s Magnetic Field: As the solar wind approaches Earth, it interacts with the planet’s magnetic field, causing some charged particles to enter the atmosphere near the poles.
    • Interaction with Gases: These particles interact with gases in the upper atmosphere, producing colourful flashes of light. Collision with oxygen produces green light, while interaction with nitrogen results in shades of blue and purple.

    Reasons for Aurora in Ladakh:

    • Intense Solar Activity: Auroras can extend to lower latitudes during periods of intense solar activity, such as solar flares and coronal mass ejections (CMEs).
      • The CMEs are from the AR13664 region of the sun that has produced several high-energy solar flares
    • Localized magnetic anomalies: Variations in Earth’s magnetic field could potentially influence the occurrence of auroras in specific areas, including regions at lower latitudes.

    Impact on Tech Infrastructure 

    • Auroras can pose challenges to space-dependent technologies and operations.
    • Disruptions in Global Positioning Systems (GPS), radio communications, flight operations, power grids, and space exploration endeavors may occur during such events.

    PYQ:

    [2022] If a major solar storm (solar flare) reaches the Earth, which of the following are the possible effects on the Earth?

    1. GPS and navigation systems could fail.
    2. Tsunamis could occur at equatorial regions.
    3. Power grids could be damaged.
    4. Intense auroras could occur over much of the Earth.
    5. Forest fires could take place over much of the planet.
    6. Orbits of the satellites could be disturbed.
    7. Shortwave radio communication of the aircraft flying over Polar Regions could be interrupted.

    Select the correct answer using the code given below:

    (a) 1, 2, 4 and 5 only
    (b) 2, 3, 5, 6 and 7 only
    (c) 1, 3, 4, 6 and 7 only
    (d) 1, 2, 3, 4, 5, 6 and 7

     

  • Positive Indian Ocean Dipole (IOD) to aid Monsoon this year

    Why in the News?

    Australian weather agencies predict the possible return of a positive Indian Ocean Dipole (IOD) in the latter half of 2024.

    What is the Indian Ocean Dipole (IOD)?

    • The IOD is also known as the Indian Nino. It is characterized by the differential heating of ocean waters in the eastern and western parts of the basin.
    • Similar to the El Nino Southern Oscillation (ENSO) in the Pacific, the IOD involves phases of ocean temperatures and atmospheric conditions that affect weather patterns across the region and beyond.
    • There are two main phases of the IOD:
      • Positive Phase: In this phase, the western Indian Ocean becomes warmer than average, and the eastern part cooler than average. This results in greater convection and rainfall over the western Indian Ocean and adjacent land areas like East Africa, while reducing rainfall over the eastern Indian Ocean and places like Indonesia and Australia.
      • Negative Phase: The opposite conditions prevail during this phase, with cooler waters in the western Indian Ocean and warmer waters in the east. This leads to increased rainfall in the eastern Indian Ocean regions and drier conditions in the western part and East Africa.

    Back2Basics: El Nino-Southern Oscillation (ENSO)

    • El Nino and La Nina are two opposite phases of the El Nino-Southern Oscillation (ENSO) cycle.
    • ENSO is a naturally occurring phenomenon that involves the interaction between the ocean and atmosphere in the equatorial Pacific.

    Here is a detailed comparison of El Nino and La Nina

    El Nino La Nina
    Definition Warmer-than-normal sea surface temperatures Cooler-than-normal sea surface temperatures
    Frequency Every two to seven years Every two to seven years
    Duration Several months to a year or more Several months to a year or more
    Impact on winds Weakens trade winds, leading to changes in patterns Strengthens trade winds, leading to changes in patterns
    Impact on rains Reduces rainfall and can cause droughts Increases rainfall and can cause flooding
    Impact on temp. Warmer-than-average temperatures Colder-than-average temperatures
    Global effects Droughts in Asia and Africa, floods in Americas Floods in Asia and Africa, droughts in South America

     

    Impact on the Indian Monsoon:

    The Indian Ocean Dipole has significant impacts on the Indian monsoon system:

    1. Positive IOD often coincides with a stronger Southwest Monsoon, bringing more rainfall to India. This is due to the shift in warm water and accompanying convection towards India, which enhances the monsoon rainfall.
    2. Negative IOD can weaken the Southwest Monsoon, resulting in less rainfall and potential drought conditions in India. The shift of warm water away from India reduces the necessary heat and moisture that drive the monsoon rains.

    PYQ:

    [2017] With reference to ‘Indian Ocean Dipole (IOD)’ sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct?

    1. IOD phenomenon is characterised by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean.

    2. An IOD phenomenon can influence an El Nino’s impact on the monsoon.

    Select the correct answer using the code given below:

    (a) 1 only

    (b) 2 only

    (c) Both 1 and 2

    (d) Neither 1 nor 2

  • Eta Aquariid Meteor Shower and how it can be spotted

    Why in the news?

    • The Eta Aquariid meteor shower, an annual event, will reach its peak on May 5 and 6.
    • This meteor shower is a result of Earth intersecting with the debris trail left by Halley’s Comet during its orbit.

    Halley’s Comet

    • Halley’s Comet is a short-period comet visible from Earth every 75–79 years.
    • It was last seen in Earth’s skies in 1986 and was met in space by an international fleet of spacecraft. It will return in 2061 on its regular journey around the Sun.

    What are Meteoric Showers?

    • Meteors, fragments of dust, rock and ice, are expelled from comets during their celestial orbits around the sun.
    • The Earth’s atmosphere heats these space rocks as they descend, leaving luminous streaks of gas in their way.
    • NASA’s records confirms existence of over 30 meteor showers annually.

    Origin of Meteor Showers:

    • Meteor showers originate from comets, remnants of the solar system’s formation composed of dust, rock, and ice.
    • Comets orbit the Sun in highly elliptical paths, and as they approach, they heat up, releasing gases and dust to form a glowing head and a tail stretching millions of miles.
    • When Earth traverses through the debris left behind by comets along their orbital plane, we witness meteor showers.

    About Eta Aquariids

    • Known for their rapid speed, Eta Aquariid meteors produce long, glowing tails lasting several minutes.
    • Observers in the Southern Hemisphere can witness approximately 30 to 40 meteors per hour during the peak, while those in the Northern Hemisphere may see around 10 meteors per hour.
    • They seem to originate from the Aquarius constellation, hence the name ‘Eta Aquariid.’

    PYQ:

    [2014] What is a coma, in the content of astronomy?

    (a) Bright half of material on the comet

    (b) Long tail of dust

    (c) Two asteroids orbiting each other

    (d) Two planets orbiting each other

  • Mapping: Garo Hills

    Why in the news?

    • Geological Survey of India (GSI) explorers have made a breakthrough, uncovering ancient fossils in Tolegre, South Garo Hills of Meghalaya.
    • It is speculated that the fossils could be linked to the genera Rhodocetus or Amulocetus (now extinct), considered ancestors of modern whales.

    About Garo Hills

    • The Garo Hills, located in Meghalaya, are part of the Garo-Khasi range, one of the hill ranges in the northeastern region of India.
    • They are situated in the western part of Meghalaya, bordering Bangladesh to the south and west.
    • The terrain of the Garo Hills is rugged and hilly, characterized by dense forests, steep slopes, and deep valleys.
    • The Nokrek is highest Peak, which stands at approximately 1,415 meters (4,642 feet) above sea level.
    • The climate in the Garo Hills is typically humid subtropical, with heavy rainfall during the monsoon season, which usually lasts from June to September.
    • Numerous rivers and streams, including the Brahmaputra, Someshwari, and Jinjiram rivers crisscross this region.
    • The region is also known for its picturesque waterfalls, such as the Pelga Falls, located near Tura, the largest town in the Garo Hills.
    • The Nokrek National Park, located within, is recognized as a UNESCO Biosphere Reserve and is home to various endangered species, including the Asian elephant and the red panda.
    • The Garo Hills are inhabited predominantly by the Garo tribe, one of the major ethnic groups in Meghalaya.

     

    PYQ:

    [2013] Consider the following pairs:

    1. Nokrek Bio-Sphere Reserve : Garo Hills

    2. Logtak (Loktak) Lake : Barail Range

    3. Namdapha National Park: Daphla Hills

    Which of the above pairs is/are correctly matched?

    (a) 1 only

    (b) 2 and 3 only

    (c) 1, 2 and 3

    (d) None

  • Mapping: Hopen Island in the Svalbard Archipelago

    Why in the news?

    Researchers disclosed that one of Norway’s Hopen Island in the Svalbard Archipelago witnessed its first walrus death due to Bird Flu (H5N1).

    About Hopen Island in the Svalbard Archipelago

    • Hopen Island is situated in the southern part of the Svalbard Archipelago, between the Barents Sea and the Greenland Sea.
    • The island covers an area of about 47 square km, making it one of the smaller islands in the Svalbard group.
    • The landscape mainly consists of low-lying tundra, rocky outcrops, and coastal cliffs.
    • Like the rest of Svalbard, Hopen Island experiences a harsh Arctic climate. Winters are long, dark, and extremely cold, while summers are short and cool.
    • It serves as an important breeding ground for seabirds such as guillemots, puffins, and kittiwakes. Polar bears are also occasionally spotted on the island, along with walruses, seals, and Arctic foxes.
    • It is uninhabited and largely inaccessible to humans due to its remote location and extreme weather conditions.
    • Historically, Hopen Island has been of strategic importance due to its location between the Barents Sea and the Greenland Sea.

    H5N1 Bird Flu: Details

    • H5N1 originated from a virus outbreak on a goose farm in China in 1996 and has since evolved into a highly pathogenic strain.
    • The virus quickly spread from Europe to Africa, Asia, North America, and South America, and most recently, it reached mainland Antarctica.
    • H5N1 is a subtype of the influenza A virus that causes severe respiratory disease in birds, known as avian influenza or “bird flu”.
    • Influenza A viruses are classified by subtypes based on the properties of their surface proteins, with H5N1 being one subtype.

    How widespread is it?

    • The virus has affected birds in over 80 countries, resulting in mass culling of poultry and wild birds.
    • Furthermore, it has now begun infecting mammals, including seals, sea lions, and marine mammals.
    • While humans rarely contract bird flu, those at risk are typically individuals who have extensive contact with infected birds at poultry farms.
    • Bird flu first broke out in Maharashtra in 2006.
    • The H5N1 virus led to the culling of millions of poultry so as to contain the virus. But it has resurfaced from time to time.

     

    PYQ:

    [2014] Which one of the following pairs of islands is separated from each other by the ‘Ten Degree Channel’?

    (a) Andaman and Nicobar

    (b) Nicobar and Sumatra

    (c) Maldives and Lakshadweep

    (d) Sumatra and Java

  • [PREMIUM] To the South Pole – Antarctica

    Why in the news?

    The Antarctic Treaty has sparked debates among policymakers, scientists, and the public, as they weigh the balance between environmental conservation, economic interests, and geopolitical concerns in Antarctica.

    About Antarctica

      • Antarctica is the fifth-largest continent, covering an area of approximately 14 million square km.
      • It is situated entirely within the Antarctic Circle, with its geographic center near the South Pole.
      • It is the coldest, driest, and windiest continent on Earth.
      • The interior of Antarctica is a polar desert, receiving very little precipitation, mostly in the form of snow.
    • The Antarctic Ice Sheet is the largest single mass of ice on Earth, containing approximately 70% of the world’s freshwater.

    Geographical Features:

    Description
    Mountains
    • The continent is home to several mountain ranges, including the Transantarctic Mountains.
    • Vinson Massif is the highest peak at 4,892 meters (16,050 feet) above sea level.
    Ice Shelves Large floating ice shelves extend along the coast, formed by glaciers flowing from the interior, crucial for stabilizing the Antarctic ice sheet.
    Glaciers Numerous glaciers flow from the high interior to the coast, including Pine Island Glacier and Thwaites Glacier, among the largest and fastest-moving in the world.
    Icebergs
    • Glaciers calve off large chunks of ice, forming icebergs of various sizes.
    • Antarctic Iceberg A-68, which broke off from the Larsen C Ice Shelf in 2017, was one of the largest recorded.
    Plateaus Much of Antarctica’s interior consists of high, flat plateaus covered by ice, reaching elevations over 4,000 meters (13,000 feet) above sea level.
    Ice-Free Areas Despite being predominantly ice-covered, some ice-free areas exist along the coastlines and in the Antarctic Peninsula region, supporting limited vegetation and wildlife.

    Territorial Claims on Antarctica:

    The countries with territorial claims in Antarctica are:

    1. Argentina: Claims a sector of Antarctica known as Argentine Antarctica.
    2. Australia: Claims the Australian Antarctic Territory.
    3. Chile: Claims a sector of Antarctica known as Chilean Antarctic Territory.
    4. France: Claims a sector of Antarctica known as Adélie Land.
    5. New Zealand: Claims the Ross Dependency.
    6. Norway: Claims a sector of Antarctica known as Queen Maud Land.
    7. United Kingdom: Claims a sector of Antarctica known as the British Antarctic Territory.
    8. United States: Claims a sector of Antarctica known as the Marie Byrd Land.

    India’s Antarctic Outreach

    • Initiated in 1981, India’s Antarctic Program, managed by National Centre for Polar and Ocean Research, encompasses multi-disciplinary research expeditions.
    • With the establishment of research bases like Dakshin Gangotri (1983) (now decommissioned), Maitri (1989), and Bharati (2012), India contributes significantly to Antarctic exploration.
    • Notably, India’s presence in Antarctica includes a Post Office established in 1984, facilitating communication and research logistics.

     

    PYQ:

    [2011] The formation of ozone hole in the Antarctic region has been a cause of concern. What could be the reason for the formation of this hole?

    (a) Presence of prominent tropospheric turbulence; and inflow of chlorofluorocarbons

    (b) Presence of prominent polar front and stratospheric’: Clouds; and inflow of chlorofluorocarbons

    (c) Absence of polar front and stratospheric clouds; and inflow of methane and chlorofluorocarbons

    (d) Increased temperature at polar region due to global warming.

  • Taam Ja’: World’s Deepest Blue Hole

    Why in the news?

    Researchers have made a discovery in Mexico, uncovering the world’s deepest blue hole, known as Taam Ja’ Blue Hole (TJBH).

    What are Blue Holes?

    • Blue holes, such as TJBH, are formed in coastal regions with soluble bedrock, such as limestone, marble, or gypsum.
    • Water percolates through the rock, dissolving minerals and widening cracks, ultimately leading to the formation of sinkholes.
    • Famous examples: 410-foot Great Blue Hole in Belize, the 663-foot Dean’s Blue Hole in the Bahamas and the 328-foot Blue Hole in the Red Sea near Dahab, Egypt.

    About Taam Ja’ Blue Hole (TJBH)

    • TJBH extends at least 1,380 feet (420 meters) below sea level, making it the deepest known underwater sinkhole in the world.
    • It is located in Chetumal Bay off the southeast coast of the Yucatan Peninsula.
    • It was first discovered in 2021, was originally thought to be 900 feet deep.
    • This discovery surpasses the previous record-holder, the Sansha Yongle Blue Hole in the South China Sea, by an impressive 480 feet.

    Research Expedition and Findings

    • Scientists utilized a conductivity, temperature, and depth (CTD) profiler to collect data about the environmental conditions within the blue hole.
    • Despite reaching depths of 1,640 feet (500 meters), the CTD profiler was unable to reach the bottom of TJBH, indicating its remarkable depth.
    • Data from the profiler suggested the presence of different water layers within the blue hole, with conditions resembling those of the Caribbean Sea at depths below 1,312 feet (400 meters).

    PYQ:

    [2017] In the context of mitigating the impending global warming due to anthropogenic emissions of carbon dioxide, which of the following can be the potential sites for carbon sequestration?

    1. Abandoned and uneconomic coal seams.

    2. Depleted oil and gas reservoirs.

    3. Subterranean deep saline formations.

    Select the correct answer using the code given below:

    (a) 1 and 2 only

    (b) 3 only

    (c) 1 and 3 only

    (d) 1, 2 and 3

  • Why the Thar Desert on the borders of India and Pakistan is getting greener?

    Why in the News?

    Rajasthan’s barren Thar Desert may turn green, says a recent study in the journal Earth’s Future.

    Thar Desert

    • The Thar Desert is the 18th largest subtropical desert globally and is one of the most densely populated deserts.
    • Approximately 40% of the human population in Rajasthan resides in the Thar Desert.
    • It extends from the Sutlej River and is bounded by the Rann of Kutch, the Aravalli Mountains, and the Indus River.
    • About 85% of the Thar Desert is located in India, with the remainder in Pakistan.
    • In India, it spans across Rajasthan, Gujarat, Haryana, and Punjab as well.
    • Civilizations are believed to have thrived in the Thar region around 50,000 years ago across the extinct Saraswati River.
    • The Desert National Park (home to the endangered Great Indian Bustard, desert fox, desert cat, blackbuck, and Indian gazelle) is situated in the Thar Desert in the northwest Indian state of Rajasthan.

    Why is the Thar desert getting greener?

    • Climate Change Effects:
        • Alteration of Weather Patterns: Climate change is causing shifts in rainfall distribution in the thar desert area.
        • Potential for Vegetation Growth: The increased precipitation could provide favorable conditions for vegetation growth, contributing to the greening of the desert.
    • Indian Monsoon Dynamics:
        • Westward Extension of Indian Monsoon: The Indian monsoon, known for bringing heavy rainfall to eastern India, is now extending further westward into regions like the Thar Desert.
        • Impact on Moisture and Rainfall: This change in monsoon dynamics could lead to increased moisture and rainfall in the desert region, facilitating the growth of vegetation.
    • Expansion of Indian Ocean Warm Pool (IOWP):
        • Influence on Monsoon Patterns: The Indian Ocean Warm Pool (IOWP) influences monsoon patterns and rainfall distribution over the Indian subcontinent.
        • Westward Expansion due to Climate Change: Climate change is causing the IOWP to expand westward, potentially resulting in increased rainfall over semi-arid regions like the Thar Desert and promoting greening.
    • Water Management Practices:
        • Contribution to Greening: Effective water management practices, such as rainwater harvesting and irrigation techniques like johad, kuis, and kunds, may be playing a role in the greening of the Thar Desert.
        • Utilization of Water Resources: By harnessing and efficiently utilizing available water resources, local communities and authorities can support vegetation growth and ecosystem restoration efforts in the desert.
    • Introduction of Irrigation  
      • Commercial Cropping: Irrigation was introduced during British colonial rule in the 19th and 20th centuries to convert arid and semi-arid ecosystems into cropland.
      • Restrictions on Grazing: The right to graze animals was restricted to landowners who cultivated crops, leading to the transformation of nomadic pastoralists into sedentary agro-pastoralists.

    PYQ:

    [2018] Which of the following leaf modifications occur(s) in the desert areas to inhibit water loss?

    1. Hard and waxy leaves
    2. Tiny leaves
    3. Thorns instead of leaves

    Select the correct answer using the code given below:

    (a) 2 and 3 only

    (b) 2 only

    (c) 3 only

    (d) 1, 2 and 3

    [2020] The process of desertification does not have climate boundaries. Justify with examples.

    [2013] Major hot deserts in northern hemisphere are located between 20-30 degree north and on the western side of the continents. Why?

  • Anticyclones, hanging even now over India, link warming to heat | Explained

    Why in the news?

    The record warming of 2023 has so far not been fully explained since it was much warmer than expected just from the superposition of El Nino on global warming.

    About Anticyclone:

    • An anticyclone is a weather phenomenon defined as a large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

    The link between ElNino and Anticyclone: 

    • El Nino events can lead to the formation of anticyclone events. During El Niño, the weakening or reversal of the Walker circulation and strengthening of the Hadley circulation caused warm ocean water to develop in the central and east-central equatorial Pacific.

    The link between anticyclone and heat 

    • Stability and Weather Patterns: Anticyclones are areas of high pressure in the atmosphere characterized by descending air, which stop the cloud formation and precipitation. This stable air mass tends to promote clear skies and can lead to prolonged periods of hot and dry weather.
    • Amplification by Global Warming: Studies suggest that global warming can intensify anticyclones, making them stronger and more persistent. Warmer temperatures due to climate change can enhance the evaporation of moisture from land and water surfaces, further reinforcing the stability of anticyclonic conditions.
    • Feedback Loop: Anticyclones can create a feedback loop with global warming. As anticyclones persist, they can exacerbate heatwaves by trapping heat near the surface, preventing it from escaping into the upper atmosphere. This trapped heat can then further strengthen the anticyclone, leading to a self-reinforcing cycle of heat and stability.

    What are the stages of early warnings?

    The stages of early warnings on the ‘ready-set-go’ system for disaster management

    • Ready: This stage involves providing a seasonal outlook based on background states and external factors like global warming and El Niño. The aim is to maximize the accuracy of longer-lead forecasts, enabling organizations like the National Disaster Management Agency (NDMA) and local governments to prepare their disaster response systems accordingly.
    • Set: In this stage, subseasonal predictions for weeks two to four are utilized. Resource allocations are made, and potential hotspots are identified to ensure that disaster preparedness is in place. This step involves moving resources, including personnel, to areas that are identified as at risk based on the extended range forecasts.
    • Go: The final stage, based on short- and medium-range forecasts (days 1-10), involves the activation of disaster response efforts. This includes implementing rescue operations, setting up hydration centers, heat shelters, and other necessary measures to manage the disaster effectively.

    Conclusion: All evidence suggests India’s prediction system and early warning systems continue to improve and the NDMA has worked these details well into its ‘ready-set-go’ system.The remaining challenges are to build resilience for the future by better predicting the trajectory of the weather at every location over India.

    Mains PYQ 

    Q Drought has been recognized as a disaster in view of its spatial expanse, temporal duration, slow onset and lasting effects on vulnerable sections. With a focus on the September 2010 guidelines from the National Disaster Management Authority (NDMA), discuss the mechanisms for preparedness to deal with likely El Nino and La Nina fallouts in India.

    https://www.thehindu.com/sci-tech/science/anticyclones-hanging-even-now-over-india-link-warming-to-heat/article68117359.ece

  • In news: Pripyat River

    Why in the news?

    • The WWF has issued a stark warning regarding the dredging of the Pripyat River, adjacent to the Chernobyl nuclear disaster site.
    • Concerns mount as the Pripyat River could transform into a permanent repository of radioactive substances, contaminating the water and food sources.

    About Pripyat River

    • Pripyat River is a significant waterway in Eastern Europe. It flows through Ukraine, Belarus, and a small portion of Russia.
    • It is primarily situated within the Polesian Lowland, a region characterized by marshes, wetlands, and forests.
    • The Pripyat River is approximately 761 km (473 miles) long.
    • Physical Features:
    • Tributaries: It has numerous tributaries, including the Stokhid River, Styr River, and Horyn River. The largest tributary of the Pripyat is the Teterev River, which joins it from the right bank.
    • Drainage Basin: Its basin covers an area of around 121,000 square kilometers (46,700 square miles). It is one of the major tributaries of the Dnieper River, which eventually flows into the Black Sea.

    Notable event: The Pripyat River gained international attention due to its proximity to the Chernobyl Nuclear Power Plant, where the catastrophic nuclear accident occurred in 1986.

    About Chernobyl Nuclear Disaster

    • The Chernobyl Disaster occurred on April 26, 1986.
    • It took place at the Chernobyl Nuclear Power Plant, near the town of Pripyat in northern Ukraine, then part of the Soviet Union.
    • The explosion and subsequent fire released a large amount of radioactive material such as cesium-137 and strontium-90 into the atmosphere, resulting in widespread contamination.

     

    PYQ:

    [2020] Consider the following pairs?

    River — Flows into

    1. Mekong — Andaman sea
    2. Thames — Irish Sea
    3. Volga — Caspian Sea
    4. Zambezi — Indian Ocean

    Which of the pairs above is/are correctly matched?

    (a) Only 1

    (b) Only 2

    (c) Only 3

    (d) None of the above/More than one of the above