Which phenomenon leads to the formation of metamorphic rocks?

A. cooling of magma

B. deposition of sediments

C. heat and pressure

D. melting of rocks

E. minerals dissolving in water

When the igneous rock is deep underground for many years, it will form into metamorphic rock under extreme pressure and temperature. It could also form into magma when it melts deep beneath the layers of earth or it could form sediments when subjected to weather erosion. The answer is letter C.