The correct answer is A. 3000 m.
Dry alpine forests are found in the high mountains of the world, between the tree line and the snow line. They are characterized by a sparse tree cover, with only a few species of trees able to survive the harsh conditions. The average elevation of dry alpine forests is around 3000 meters.
The districts of Kinnaur, Lahaul and Spiti are located in the Indian state of Himachal Pradesh. They are all high-altitude regions, with an average elevation of over 3000 meters. The dry alpine forests found in these districts are home to a variety of plants and animals, including snow leopards, blue sheep, and ibex.
Option B is incorrect because the average elevation of dry alpine forests is not 7500 meters. Option C is incorrect because the average elevation of dry alpine forests is not 6000 meters. Option D is incorrect because the average elevation of dry alpine forests is not 1500 meters.