Evaluate the Integral $\int_{0}^{\pi / 2} \cos ^{6} x d x$

Multiple Choice

Evaluate the integral. $\int_{0}^{\pi / 2} \cos ^{6} x d x$

A) $\frac{5}{32} \pi$
B) $\frac{3}{16} \pi$
C) $\frac{5}{16} \pi$
D) $\frac{3}{32} \pi$