Find the Values of X for Which the Expression Equals $$\sqrt { 4 - x ^ { 2 } } - x \left( \frac { 1 } { 2 } \right) \frac { 1 } { \sqrt { 4 - x ^ { 2 } } } ( 2 x )$$

Multiple Choice

Find the values of x for which the expression equals zero.
- $$\sqrt { 4 - x ^ { 2 } } - x \left( \frac { 1 } { 2 } \right) \frac { 1 } { \sqrt { 4 - x ^ { 2 } } } ( 2 x )$$

A) $\{ \pm \sqrt { 2 } \}$
B) $\{ \sqrt { 2 } , 2 \}$
C) $\{ \pm 2 \}$
D) $\{ \pm \sqrt { 2 } , \pm 2 \}$