Write the Following as an Algebraic Expression in U, U $\cos ( \arcsin u )$

Write the following as an algebraic expression in u, u > 0.
- $\cos ( \arcsin u )$

A) $\frac { \sqrt { \mathrm { u } ^ { 2 } + 1 } } { \mathrm { u } }$
B) $\sqrt { u ^ { 2 } - 1 }$
C) $\sqrt { \mathrm { u } ^ { 2 } + 1 }$
D) $\sqrt { 1 - u ^ { 2 } }$