The correct answer is: C. Kinnaur and Kullu
Kinnaur and Kullu are two districts in Himachal Pradesh that receive adequate rainfall for growing various crops. The average annual rainfall in Kinnaur is 1,500 mm, while the average annual rainfall in Kullu is 1,200 mm. This rainfall is sufficient for growing a variety of crops, including rice, wheat, maize, and barley.
The other options are incorrect because they do not receive adequate rainfall for growing various crops. Lahaul and Spiti are two districts in Himachal Pradesh that receive very little rainfall. The average annual rainfall in Lahaul is 200 mm, while the average annual rainfall in Spiti is 100 mm. This rainfall is not sufficient for growing most crops. Solan and Sirmaur are two districts in Himachal Pradesh that receive moderate rainfall. The average annual rainfall in Solan is 800 mm, while the average annual rainfall in Sirmaur is 700 mm. This rainfall is sufficient for growing some crops, but not all crops.