Assertion (A): The Sundarban delta is formed by the Ganga and the Brahmaputra rivers.
Reason (R): The Sundarban delta gets its name from the Sundari tree, which grows well in marshland.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Both Assertion (A) and Reason (R) are correct, but R is not the correct explanation of A.
In an Assertion-Reason question, each statement is checked for truth first, and then R is tested as the cause of what A describes.
Assertion — correct. The Ganga, joined by the Brahmaputra, flows into the Bay of Bengal, and the delta these rivers build there is the Sundarban delta.
Reason — correct. The delta is named after the Sundari tree, which grows well in its marshy land.
R tells only how the delta got its name; a delta is built by the silt the rivers bring, not by its trees, so R does not explain A.