What is the system of governance in the Panchayati Raj setup

(a)

Single-tier structure of local self-government at the village level

(b)

Two-tier system of local self-government at the village and block levels

(c)

Three-tier structure of local self-government, at the village, block and district levels

(d)

Four-tier system of local self-government at the village, block, district and state levels