The correct answer is: a) Stalactites and stalagmites.
Belum Caves are a group of limestone caves located in the Kurnool district of Andhra Pradesh, India. The caves are known for their stalactites and stalagmites, which have been forming for millions of years. The caves are also home to a variety of bats and other wildlife.
Stalactites are formations that hang from the ceiling of a cave, while stalagmites grow up from the floor. Both stalactites and stalagmites are formed by the deposition of calcium carbonate from water that seeps through the limestone rock. The water dissolves the calcium carbonate and carries it away, but as it evaporates, the calcium carbonate is deposited back on the cave walls and floor. Over time, these deposits can form large and impressive structures.
The Belum Caves are one of the most popular tourist destinations in Andhra Pradesh. The caves are open to the public and can be visited on a guided tour.