#### Answer

The correct answer is:
(b) the depth of the water at the location of the dam

#### Work Step by Step

The water at the location of the dam exerts pressure on the wall of the dam. The magnitude of this pressure depends on the depth of the water at the location of the dam. The water that is deeper below the surface exerts a higher pressure on the dam. The average pressure exerted by the water is greater if the depth of the water at the location of the dam is greater.
The dam pushes back on the water at the location of the dam with the same pressure that the water applies, and the force that the dam exerts on the water is proportional to this pressure.
The correct answer is:
(b) the depth of the water at the location of the dam