The correct answer is: C. Kangra
Kangra district has the highest density of population in Himachal Pradesh. The district has a population density of 456 persons per square kilometer. This is higher than the state average of 120 persons per square kilometer.
The high population density of Kangra district is due to a number of factors. The district is located in the central part of the state and is well-connected to other parts of the state. The district is also home to a number of important towns and cities, such as Dharamshala, Kangra, and Palampur. These towns and cities are major centers of education, healthcare, and commerce.
The high population density of Kangra district has a number of implications. The district faces a number of challenges, such as providing basic amenities to the population, managing the environment, and ensuring law and order. The district administration is working to address these challenges.
The other options are incorrect because they have a lower population density than Kangra district. Bilaspur district has a population density of 326 persons per square kilometer. Shimla district has a population density of 262 persons per square kilometer. Hamirpur district has a population density of 254 persons per square kilometer.