The correct answer is C. Kinnaur.
Great Himalayan National Park is located in the Kinnaur district of Himachal Pradesh. It is the largest national park in Himachal Pradesh and the second largest national park in India. The park was established in 1984 and covers an area of 3,900 square kilometers. The park is home to a variety of wildlife, including snow leopards, Himalayan tahr, musk deer, and blue sheep. The park is also home to a variety of plant life, including rhododendrons, magnolias, and fir trees.
Option A is incorrect because Mandi is a district in Himachal Pradesh, but Great Himalayan National Park is not located in Mandi.
Option B is incorrect because Shimla is the capital of Himachal Pradesh, but Great Himalayan National Park is not located in Shimla.
Option D is incorrect because Kullu is a district in Himachal Pradesh, but Great Himalayan National Park is not located in Kullu.