Simplify the Given Expression Algebraically $\cos \left( \frac { \pi } { 2 } + x \right)$

Multiple Choice

Simplify the given expression algebraically. $\cos \left( \frac { \pi } { 2 } + x \right)$

A) $\cos x$
B) $- \sin x$
C) $\sin x$
D) 1
E) $- \cos x$