Which river in the Southern Peninsula has the second largest river basin in India?

Answer: Option B

River basins are defined by the total area drained by a river and its tributaries.

In the Southern Peninsula of India, the Godavari River has the largest river basin, with an area of about 312,812 square kilometers.

The Krishna River has the second largest river basin in the Southern Peninsula, covering approximately 258,948 square kilometers.

Cauvery has a smaller basin, around 81,155 square kilometers.

Mahanadi, although significant, lies partly in central-eastern India and has a basin area of about 141,589 square kilometers, which is smaller than that of Krishna.

Therefore, the river in the Southern Peninsula with the second largest river basin is the Krishna River, making Option B the correct answer.