Answer:

D.Decay

Explanation:

The simple answer is that a rock may undergo metamorphosis.

High temperature can melt a rock, but if there is pressure to keep the rock solid then the chemical structure of the rock would change. It is this process that turns limestone into marble.

In the absence of sufficient pressure the rock may melt and then re-solidify. If the rock has a long slow cooling process then larger crystals can form then if there is a swift cool down.