landslides moving loose rocks downhill sediments depositing on the seafloor deltas forming at the mouth of rivers mountains building up
I gave my students this multiple choice question: Which process is the best example of a sudden change to Earth's surface?

Only one answer is correct among these 4 choices:
- landslides moving loose rocks downhill
- sediments depositing on the seafloor
- deltas forming at the mouth of rivers
- mountains building up

Could you tell me which one is correct?

landslides moving loose rocks downhill