Find the Phase Shift of the Function $$y = - 3 \cos \left( \frac { 1 } { 2 } x + \frac { \pi } { 2 } \right)$$

Multiple Choice

Find the phase shift of the function.
- $$y = - 3 \cos \left( \frac { 1 } { 2 } x + \frac { \pi } { 2 } \right)$$

A) $\frac { \pi } { 2 }$ units to the left
B) $\pi$ units to the left
C) $\frac { \pi } { 4 }$ units to the right
D) $3 \pi$ units to the right