What Is the Period of the Function $c(x)=\cos x+0.5 \cos 5 x$

Multiple Choice

What is the period of the function $c(x) =\cos x+0.5 \cos 5 x$
?

A) $2 \pi$

B) $\pi$

C) $\frac{\pi}{5}$

D) The function is not periodic