Which of the following is/are correctly matched?

1. Young fold mountains: Himalayas, Alps
2. Old fold mountains : Urals, Aravalli
3. Residual mountains : Nilgiri, Rajmahal Hills
4. All of the above.

Assertion (A): The forces of faulting lead to the formation of block mountains.

Reason (R): Block mountains are often separated by intervening basins called graben.

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.

The plains that are formed by the deposition of materials which have been brought by various agents of transportation:

1. Structural plain
2. Depositional plain
3. Polder
4. Dykes

Depositional plains formed as a result of action of wind have irregular and undulating surface because of

1. new deposits made everyday.
2. existence of sand dunes and hallows.
3. existence of scrubs.
4. All of the above.