Write an Equivalent Expression in Exponential Form $\log _ { x } 16 = - 2$

Multiple Choice

Write an equivalent expression in exponential form.
- $\log _ { x } 16 = - 2$

A) $\{ - 4 \}$
B) $\left\{ \frac { 1 } { 4 } \right\}$
C) $\{ 4 \}$
D) $\left\{ - \frac { 1 } { 4 } \right\}$