Which one among the following rivers has the largest catchment area?

The catchment area of a river refers to the total geographical area drained by the river and its tributaries.

Among the given options, the Krishna River has the largest catchment area.

The catchment area of the Krishna River is approximately 258,948 square kilometers.

In comparison:

Cauvery has a catchment area of about 81,155 sq km

Mahanadi has a catchment area of about 141,589 sq km

Narmada has a catchment area of about 98,796 sq km

Therefore, Option B: Krishna is the correct answer as it drains the largest area among the listed rivers.