A large mass of ice and snow accumulates. A mound of sand is built by wind. A low area of land is surrounded by mountains. A mass of sediment is deposited at the mouth of a river.
I gave my students this multiple choice question: Which statement describes the formation of a delta?

Only one answer is correct among these 4 choices:
- A large mass of ice and snow accumulates.
- A mound of sand is built by wind.
- A low area of land is surrounded by mountains.
- A mass of sediment is deposited at the mouth of a river.

Could you tell me which one is correct?

A mass of sediment is deposited at the mouth of a river.