The correct answer is: A. West Champaran
As per India State of Forest Report, 2017, West Champaran district has the highest percentage of forest cover in Bihar, with 31.79% of its total geographical area under forest cover. The other options are incorrect because they have a lower percentage of forest cover than West Champaran.
- Kaimur (Bhabua) has 28.92% forest cover.
- Nalanda has 22.78% forest cover.
- East Champaran has 22.56% forest cover.
The forest cover in Bihar is 23.92%, which is lower than the national average of 24.56%. The state government has taken several initiatives to increase the forest cover in Bihar, such as the Van Mahotsav and the Hariyali Abhiyan.