Find the Exact Value of the Composition $$\cos ^ { - 1 } \left( \cos \left( - \frac { \pi } { 6 } \right) \right)$$

Multiple Choice

Find the exact value of the composition.
- $$\cos ^ { - 1 } \left( \cos \left( - \frac { \pi } { 6 } \right) \right)$$

A) $\frac { 5 \pi } { 6 }$
B) $\frac { 7 \pi } { 6 }$
C) $- \frac { \pi } { 6 }$
D) $\frac { \pi } { 6 }$