Write the Following as an Algebraic Expression in U, U $\sin \left( \arctan \frac { \mathrm { u } } { \sqrt { 5 } } \right)$

Multiple Choice

Write the following as an algebraic expression in u, u > 0.
- $\sin \left( \arctan \frac { \mathrm { u } } { \sqrt { 5 } } \right)$

A) $\frac { \sqrt { u ^ { 2 } + 5 } } { u ^ { 2 } + 5 }$
B) $u \sqrt { u ^ { 2 } + 5 }$
C) $\frac { u \sqrt { u ^ { 2 } + 5 } } { u ^ { 2 } + 5 }$
D) $\frac { \mathrm { u } \sqrt { \mathrm { u } ^ { 2 } - 5 } } { \mathrm { u } ^ { 2 } - 5 }$