The correct answer is A. Lahaul and Spiti.
Lahaul and Spiti is a district in the Indian state of Himachal Pradesh. It is the most sparsely populated district in India, with a population of just over 30,000 people. The district is located in the Himalayas, and its climate is extremely cold and dry. The average annual rainfall in Lahaul and Spiti is just 100 mm, making it one of the driest places in India.
The other options are incorrect because they are all districts in Himachal Pradesh that receive more rainfall than Lahaul and Spiti. Kangra receives an average annual rainfall of 1,200 mm, Chamba receives an average annual rainfall of 1,000 mm, and Solan receives an average annual rainfall of 800 mm.
Lahaul and Spiti is a beautiful and remote district, but it is not for the faint of heart. The climate is harsh, and the terrain is rugged. However, for those who are looking for an adventure, Lahaul and Spiti is a great place to visit.