Fish that feed on sediment will most likely be found in rivers.
a. shallow
b. narrow
c. deep
d. fast-moving

The correct option is C.
A deep river is one which has slow movement or is stagnant. In such a river mud or silt are usually present, this is because they have time to settle down because of the slow movement or stagnancy of the water. Thus, fish that feed on sediments are usually found in such rivers.

The answer is C 
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