Let $f ( x ) = \frac { 1 - x } { 1 + x }$

Multiple Choice

Let $f ( x ) = \frac { 1 - x } { 1 + x }$ Then $f ^ { \prime } ( x )$ is

A) $- \frac { 2 } { ( 1 + x ) ^ { 2 } }$
B) $\frac { 2 } { ( 1 + x ) ^ { 2 } }$
C) $- \frac { 2 x } { ( 1 + x ) ^ { 2 } }$
D) $\frac { 2 x } { ( 1 + x ) ^ { 2 } }$
E) $- \frac { 2 } { 1 + x }$