Explanation

Under Section 38V of the Wildlife (Protection) Act, 1972, the core/critical tiger habitats of the listed reserves measure as follows:

– Nagarjunsagar-Srisailam (Andhra Pradesh): Approximately 2,595.72 sq km (The largest core/critical tiger habitat in India).
– Sunderbans (West Bengal): Approximately 1,699.62 sq km.
– Ranthambore (Rajasthan): Approximately 1,113.36 sq km.
– Corbett (Uttarakhand): Approximately 821.99 sq km.

Therefore, the reserve with the largest area under Critical Tiger Habitat is Nagarjunsagar-Srisailam — Option C.