Simplify the Expression $2 \cos ^ { 2 } 4 x - 1$

Multiple Choice

Simplify the expression.
- $2 \cos ^ { 2 } 4 x - 1$

A) $2 \sin 4 x$
B) $\cos 8 x$
C) $\frac { 1 } { 2 } \sin 16 x$
D) $\cos 4 x$