The pile-up of sand and silt at the site where a river flows into the ocean forms a

As a river flows, it picks up sediment from the river bed, eroding banks, and debris on the water. The river mouth is where much of this gravel, sand, silt, and clay—called alluvium—is deposited. When large amounts of alluvium are deposited at the mouth of a river, a delta is formed.

Explanation:

As a river flows, it picks up sediment from the river bed, eroding banks, and debris on the water.

Explanation:

the answers are

c and c