Which statement best defines metamorphic rocks?

• A. They form from cooling of magma.
• B. They are formed by weathering of rocks.
• C. They arise from the transformation of existing rock through heat and pressure.
• D. They form from deposition in sediment layers.

Answer: (C)

Metamorphic rocks form when existing rocks are transformed by heat, pressure, and chemically active fluids deep in the Earth's crust. This solid-state change rearranges minerals and can create new textures and compositions without melting. That’s why the best description is that metamorphic rocks arise from the transformation of existing rock through heat and pressure. In contrast, cooling of magma produces igneous rocks, weathering and erosion break rocks down to sediments that can lithify into sedimentary rocks, and deposition in layers also points to sedimentary rock formation.