Use a Double Angle Formula to Rewrite the Given Expression $10 \cos ^ { 2 } x - 5$

Multiple Choice

Use a double angle formula to rewrite the given expression. $10 \cos ^ { 2 } x - 5$

A) $5 \cos 5 x$
B) $5 \cos 2 x$
C) $10 \cos 2 x$
D) $2 \cos 10 x$
E) $2 \cos 5 x$