Find the Amplitude, Period, and Phase Shift of the Function $y = 2 \cos \left( \frac { 1 } { 2 } x - \frac { \pi } { 6 } \right)$

Multiple Choice

Find the amplitude, period, and phase shift of the function. $y = 2 \cos \left( \frac { 1 } { 2 } x - \frac { \pi } { 6 } \right)$

A) Amplitude 1/2, Period $4 \pi$ , phase shift $\pi / 3$

B) Amplitude 1/2, Period $2 \pi$ , phase shift $\pi / 3$

C) Amplitude 2, Period $\pi$ , phase shift $\pi / 6$

D) Amplitude 2, Period $4 \pi$ , phase shift $\pi / 6$

E) Amplitude 2, Period $4 \pi$ , phase shift $\pi / 3$