Assertion (A): The Northern Plains comprises riverine soil.

Reason (R): Riverine soil is a mixture of sand, clay and silt.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R does not explain A.
3. A is true but R is false.
4. A is false but R is true.

Both A and R are true and R is the correct explanation of A.

Explanation — The northern plains of India, especially areas like the Indo-Gangetic plains, are made up of Riverine (alluvial) soil deposited by rivers. These riverine soils are formed by deposition of materials like sand, clay and silt.