Use the Half-Angle Formula to Simplify the Given Expression $$\sqrt { \frac { 1 + \cos 16 x } { 2 } }$$

Multiple Choice

Use the half-angle formula to simplify the given expression.
$$\sqrt { \frac { 1 + \cos 16 x } { 2 } }$$

A) $\cos 32 x$
B) $\cos 8 x$
C) $\cos 16 x$
D) $\cos 64 x$
E) $\cos 4 x$