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 am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which statement describes the formation of a delta?
Possibilities:
- 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.

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