Solve for X $\left( \frac { 1 } { 4 } \right) ^ { x } = 64$

Solve for x.​ $\left( \frac { 1 } { 4 } \right) ^ { x } = 64$ ​

A) 4
B) $$- 3$$
C) 7
D) 3
E) $- 4$