The rocks have been melted by a magma. The rocks have been broken by faults. The rocks have been weathered by water. The rocks have been folded by pressure.
I gave my students this multiple choice question: Which is the best evidence that rocks found deep underground were once exposed at the surface?

Only one answer is correct among these 4 choices:
- The rocks have been melted by a magma.
- The rocks have been broken by faults.
- The rocks have been weathered by water.
- The rocks have been folded by pressure.

Could you tell me which one is correct?

The rocks have been weathered by water.