The correct answer is: A. Nalagarh Fort.
Nalagarh Fort is a 16th-century fort located in Nalagarh town in the Solan district of Himachal Pradesh, India. It is also known as Nalapani Fort. The fort was built by Raja Nala of the Katoch dynasty in the 16th century. It was later renovated by Raja Sansar Chand of Kangra in the 18th century. The fort is a fine example of Mughal architecture. It is surrounded by a moat and has a number of bastions. The fort houses a number of temples, including the Nalagarh Palace Temple and the Nalagarh Fort Temple. The fort is a popular tourist destination.
The other options are incorrect because:
- Kalanga Fort is a 16th-century fort located in the Kalanga town in the Una district of Himachal Pradesh, India. It is not known as Nalapani Fort.
- Nurpur Fort is a 16th-century fort located in the Nurpur town in the Kangra district of Himachal Pradesh, India. It is not known as Nalapani Fort.
- Taragarh Fort is a 16th-century fort located in the Taragarh town in the Shimla district of Himachal Pradesh, India. It is not known as Nalapani Fort.