The correct answer is: c) Folding and faulting.
The hill ranges of Mizoram were formed primarily due to folding and faulting. Folding is the process by which rocks are bent into folds, while faulting is the process by which rocks are broken and displaced. These processes are caused by the movement of tectonic plates, which are the large pieces of Earth’s crust that float on the mantle.
Volcanic activity is the process by which molten rock, or magma, rises to the surface and erupts through volcanoes. Glaciation is the process by which glaciers, which are large masses of ice, move over the land. Erosion by rivers is the process by which rivers carry away soil and rock from the land.
While all of these processes can contribute to the formation of mountains, folding and faulting are the primary causes of the hill ranges of Mizoram.