Solve $\left( \frac { 1 } { 2 } \right) ^ { x } = 8$

Multiple Choice

Solve $\left( \frac { 1 } { 2 } \right) ^ { x } = 8$ for x.

A) 1
B) $- 1$
C) $- 3$
D) $- 2$
E) no solution