The correct answer is C. Jubbarhatti Airport.
Jubbarhatti Airport is the largest airport in Himachal Pradesh. It is located in the town of Jubbarhatti, about 11 kilometers from the state capital, Shimla. The airport was established in 1955 and has a single runway that is 2,200 meters long. It is served by a number of domestic airlines, including Air India, IndiGo, and SpiceJet.
The other options are incorrect because they are not airports in Himachal Pradesh. Kullu Airport is a small airport located in the town of Kullu. Gaggal Airport is a small airport located in the town of Gaggal. Bhuntar Airport is a small airport located in the town of Bhuntar.
Jubbarhatti Airport is the largest airport in Himachal Pradesh because it has the longest runway and is served by the most airlines. It is also the most convenient airport for travelers to Shimla, as it is located just a short drive from the city.