Which of the following is true with regard to the characteristics of the Himalayan rivers ?
1. Many of them have their sources in the inner Himalays.
2. They have a perennial flow.
3. They have a great capacity for erosion.
4. They do not form gorges.
(a) 1 and 2 (b) 1, 2 and 3 (c) 3 and 4 (d) 2 and 4
