Complete the Identity $\cos \left( \frac { 3 \pi } { 2 } - x \right) =$

Multiple Choice

Complete the identity.
- $\cos \left( \frac { 3 \pi } { 2 } - x \right) =$ ?

A) $- \sin x$
B) $\sin x$
C) $- \cos x$
D) $\cos x$