Find the Specified Quantity $y = - 4 \cos \left( 5 x + \frac { \pi } { 2 } \right)$

Multiple Choice

Find the specified quantity.
-Find the period of $y = - 4 \cos \left( 5 x + \frac { \pi } { 2 } \right)$ .

A) $\frac { 2 \pi } { 5 }$
B) 4
C) $\pi$
D) $\frac { \pi } { 2 }$