Rationalize the Denominator and Simplify $\frac { \sqrt { s } } { \sqrt { s } + \sqrt { w } }$

Multiple Choice

Rationalize the denominator and simplify. Assume that all variables represent positive real numbers.
- $\frac { \sqrt { s } } { \sqrt { s } + \sqrt { w } }$

A) $\frac { s + s \sqrt { w } } { s + w }$
B) $\frac { s - s \sqrt { w } } { s - w }$
C) $\frac { s + \sqrt { s w } } { s + w }$
D) $\frac { s - \sqrt { s w } } { s - w }$