Waterfalls are a common feature in Meghalaya’s rivers due to the:

The correct answer is: a) High rainfall and hilly terrain.

Meghalaya is a state in northeastern India that is known for its high rainfall and hilly terrain. The state receives an average annual rainfall of over 12,000 mm, which is the highest in India. The hilly terrain of Meghalaya is also a major factor in the formation of waterfalls. The rivers in Meghalaya flow through steep gorges and valleys, which causes them to drop over cliffs and form waterfalls.

The other options are incorrect because:

• Option b) Melting glaciers is not a major factor in the formation of waterfalls in Meghalaya. There are no glaciers in Meghalaya.
• Option c) Coastal erosion is not a major factor in the formation of waterfalls in Meghalaya. Meghalaya is not a coastal state.
• Option d) Volcanic activity is not a major factor in the formation of waterfalls in Meghalaya. There are no volcanoes in Meghalaya.