The correct answer is: B. Kangra
Kangra district has the highest road density in the state of Himachal Pradesh. The road density is the number of kilometers of road per 100 square kilometers of area. In Kangra district, the road density is 114.2 kilometers per 100 square kilometers. This is higher than the road density in any other district in the state.
The other options are incorrect because they have a lower road density than Kangra district. Shimla district has a road density of 102.1 kilometers per 100 square kilometers, Mandi district has a road density of 98.3 kilometers per 100 square kilometers, and Hamirpur district has a road density of 96.4 kilometers per 100 square kilometers.
The high road density in Kangra district is due to a number of factors. First, the district is located in the central part of the state, which makes it a major transportation hub. Second, the district is home to a number of important tourist destinations, such as Dharamshala and Kangra Fort. Third, the district is a major agricultural area, and the roads are essential for transporting goods and services to and from the farms.
The high road density in Kangra district has a number of benefits. It makes it easier for people to travel around the district, and it helps to promote economic development. However, it also has some drawbacks. The roads can be congested, and they can be damaged by heavy rains and snowfall.