Find the Volume of the Described Solid $y = 5 \cos x$

Multiple Choice

Find the volume of the described solid.
-The base of a solid is the region between the curve $y = 5 \cos x$ and the $x$ -axis from $x = 0$ to $x = \pi / 2$ . The cross sections perpendicular to the $x$ -axis are isosceles right triangles with one leg on the base of the solid.

A) $\frac { 25 } { 8 } \pi$
B) $6 \pi$
C) $\frac { 5 } { 2 } \pi$
D) $\frac { 25 } { 4 } \pi$