pressure from a glacier heat from magma erosion from flowing water radiation from the Sun
I gave my students this multiple choice question: Which of these actions will change a sedimentary rock, such as limestone, into a metamorphic rock, such as marble?

Only one answer is correct among these 4 choices:
- pressure from a glacier
- heat from magma
- erosion from flowing water
- radiation from the Sun

Could you tell me which one is correct?

heat from magma