Use the Fact That the Trigonometric Functions Are Periodic to Find

Multiple Choice

Use the fact that the trigonometric functions are periodic to find the exact value of the expression. Do not use a calculator.
- $$\cos \frac { 16 \pi } { 3 }$$

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