ANS:E - both (b) and (c).

Hydrostatic pressure on a dam depends upon its depth and shape. The hydrostatic pressure exerted by a fluid depends on its density, gravity, and the depth of the fluid. In the case of a dam, the hydrostatic pressure increases with the depth of the water behind the dam. The deeper the water, the greater the hydrostatic pressure exerted on the dam. Additionally, the shape of the dam affects the distribution of hydrostatic pressure along its surface. The hydrostatic pressure is distributed based on the shape and geometry of the dam. For example, a triangular dam will experience different pressure distributions compared to a rectangular or trapezoidal dam. Therefore, both the depth and shape of the dam influence the hydrostatic pressure exerted on it. Hence, the correct option is: both (b) and (c).