The correct answer is A. Kangra.
Kangra is the largest district in Himachal Pradesh, India. It is located in the state’s central region. The district is known for its tea industry, which is the largest in the state. The tea industry is located in the Kangra Valley, which is a fertile valley located in the foothills of the Himalayas. The valley is home to several tea estates, which produce a variety of teas, including black tea, green tea, and oolong tea. The tea industry is a major source of employment for the people of Kangra.
The other options are incorrect. Sirmaur is a district located in the state’s northern region. Shimla is the state capital and is located in the state’s central region. Una is a district located in the state’s southern region.