Answer:
The correct answer is option C, that is, heat and pressure.
Explanation:
The formation of metamorphic rocks takes place due to the chemical and physical alteration by pressure and heat of the prevailing sedimentary or igneous material into a denser form. Because of the activity of compression, plate tectonics, shearing forces, and stress for the prolonged time duration, the rocks can get deformed and warped, making them get trampled into a smaller space volume.
Due to this, the metamorphic rocks are always more condensed in comparison to their original substance, and also much less vulnerable to erosional dissociation. With the movement of the plates of the Earth over the geologic time, a plate comprising sedimentary or igneous rock may turn subducted underneath another plate. The absolute weight of the above substance makes the rock to go through metamorphism.
