Rationalize the Denominator and Simplify $\frac { \sqrt { t } } { \sqrt { t } + \sqrt { m } }$

Multiple Choice

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

A) $\frac { t + \sqrt { t m } } { t + m }$
B) $\frac { t - t \sqrt { m } } { t - m }$
C) $\frac { t - \sqrt { t m } } { t - m }$
D) $\frac { t + t \sqrt { m } } { t + m }$