Which of the following is formed at the mouth of a river as sediment is carried to the ocean?
a.
a lake
b.
an island
c.
a delta
d.
a bay

Option (C)

Explanation:

A river flows from a region of higher elevation to a region of lower elevation and is structurally controlled. As it flows towards the sea or ocean body, the strength of the river decreases and carries a lesser amount of sediments along with it. These sediments are sometimes deposited in a large amount in such a way that the sea waves cannot erode, thereby resulting in the formation of layers of sediments, which are commonly known as delta. A delta is considered to be the mouth of the river.

Hence, the correct answer is option (C).

polar areas, such as antarctica or the south pole.