Find the Exact Circular Function Value $$\cos \frac { - 2 \pi } { 3 }$$

Multiple Choice

Find the exact circular function value.
- $$\cos \frac { - 2 \pi } { 3 }$$

A) undefined
B) $- \frac { 1 } { 2 }$
C) $- \frac { \sqrt { 3 } } { 2 }$
D) $\frac { \sqrt { 3 } } { 2 }$