Rationalize the Denominator $\frac { \sqrt { x } - 4 } { \sqrt { x } + 4 }$

Multiple Choice

Rationalize the denominator. Assume that all variables represent positive numbers.
- $\frac { \sqrt { x } - 4 } { \sqrt { x } + 4 }$

A) $- 8 \sqrt { x }$
B) $\frac { x + 16 } { x - 16 }$
C) $\frac { x - 8 \sqrt { x } + 16 } { x - 16 }$
D) $- 1$