A goat is tied to two poles P and Q with ropes that are 15-metre long. P and Q are 20-metre apart as shown in the given diagram: Which one of the following shaded portions indicates the total area over which the goat can graze

A goat is tied to two poles P and Q with ropes that are 15-metre long. P and Q are 20-metre apart as shown in the given diagram: Which one of the following shaded portions indicates the total area over which the goat can graze ?