Why are so many big cities located along the banks of a river?

A. Rivers are a good place to swim.

B. Rivers are nice to look at.

O

C. Rivers provide a transportation route.

D. Rivers provide a convenient place for industries to release wastes.

C

Explanation:

before automobiles and trains and such, people relied on boats to deliver goods quickly, which is why most big cities are located on rivers or on the coast (ex: Boston being right on the north Atlantic coast, or Paris being right on the river Seine)

C. Rivers provide a transportation route.