an ancient river flooded an earthquake folded land tectonic plates pulled apart tectonic plates collided
I gave my students this multiple choice question: Which best explains how the Appalachian Mountains formed?

Only one answer is correct among these 4 choices:
- an ancient river flooded
- an earthquake folded land
- tectonic plates pulled apart
- tectonic plates collided

Could you tell me which one is correct?

tectonic plates collided