Evaluate the Given Expression $\left( - \frac { 2 \pi } { 3 } \right)$

Multiple Choice

Evaluate the given expression. cos $\left( - \frac { 2 \pi } { 3 } \right)$

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