Perform the Indicated Operation and Write Your Answer with Positive $$\frac { \mathrm { m } ^ { - 1 } - \mathrm { n } ^ { - 1 } } { ( \mathrm { mn } ) ^ { - 1 } }$$

Multiple Choice

Perform the indicated operation and write your answer with positive integer exponents.
- $$\frac { \mathrm { m } ^ { - 1 } - \mathrm { n } ^ { - 1 } } { ( \mathrm { mn } ) ^ { - 1 } }$$

A) $m - n$
B) $m + n$
C) $n - m$
D) $- \mathrm { n } - \mathrm { m }$