The Alpine vegetation in the western Himalayas is found only up to a height of 3000 metres, while in the eastern Himalayas it is found up to a height of 4000 metres. The reason for this variation in the same mountain range is that

1. (a)eastern Himalayas are higher than western Himalayas
2. (b)eastern Himalayas are nearer to the Equator and sea coast than western Himalayas
3. (c)eastern Himalayas get more monsoon rainfall than the western Himalayas
4. (d)eastern Himalayan rocks are more fertile than the western Himalayan rocks