The correct answer is: A. Lahaul
Big Shigai and Nohtang mountains are the main attractions of Lahaul valley. Lahaul is a valley in the Indian state of Himachal Pradesh. It is located in the Pir Panjal Range of the Himalayas, and is a popular tourist destination. The valley is home to a number of villages, as well as the town of Keylong, which is the administrative center of Lahaul district.
Big Shigai is a mountain peak located in the Lahaul valley. It is the highest peak in the valley, and is a popular destination for trekking and mountaineering. Nohtang Pass is a mountain pass located in the Lahaul valley. It is the highest pass in the valley, and is a popular destination for trekking and mountaineering.
The other options are incorrect because they are not valleys in the Lahaul valley. Solang is a town in the Kullu valley, Malana is a village in the Parvati valley, and Pangi is a valley in the Chamba district.