Write an Algebraic Expression That Is Equivalent To $$\sin \left( \arctan \frac { x } { 2 } \right)$$

Multiple Choice

Write an algebraic expression that is equivalent to $$\sin \left( \arctan \frac { x } { 2 } \right)$$ .

A) $\frac { x \sqrt { x ^ { 2 } + 4 } } { x ^ { 2 } + 4 }$
B) $\frac { 2 \sqrt { x ^ { 2 } + 4 } } { x ^ { 2 } + 4 }$
C) $\frac { 2 } { x }$
D) $\frac { \sqrt { x ^ { 2 } + 4 } } { 2 }$
E) $\frac { \sqrt { x ^ { 2 } + 4 } } { x }$