The correct answer is D. All of these.
Bilaspur, Sirmaur, and Solan are all districts in the Indian state of Himachal Pradesh. They are all rich in limestone, which is a sedimentary rock composed mainly of calcium carbonate. Limestone is used in a variety of industries, including construction, manufacturing, and agriculture.
Bilaspur is a district in the Indian state of Himachal Pradesh. It is located in the central part of the state and is bordered by the districts of Hamirpur, Kangra, Una, and Solan. The district has a population of over 1.2 million people and is the third most populous district in Himachal Pradesh. The capital of Bilaspur is the town of Bilaspur.
Sirmaur is a district in the Indian state of Himachal Pradesh. It is located in the southern part of the state and is bordered by the districts of Solan, Shimla, Kullu, and Mandi. The district has a population of over 400,000 people and is the fifth most populous district in Himachal Pradesh. The capital of Sirmaur is the town of Nahan.
Solan is a district in the Indian state of Himachal Pradesh. It is located in the central part of the state and is bordered by the districts of Bilaspur, Hamirpur, Una, and Kangra. The district has a population of over 600,000 people and is the fourth most populous district in Himachal Pradesh. The capital of Solan is the town of Solan.
All three districts are rich in limestone. Limestone is a sedimentary rock composed mainly of calcium carbonate. It is formed when the remains of marine organisms, such as coral and algae, accumulate on the seafloor and are buried over time. Limestone is used in a variety of industries, including construction, manufacturing, and agriculture.