Simplify the Expression $\left( \frac { \mathrm { c } } { \mathrm { gf } } \right) ^ { - 1 }$

Multiple Choice

Simplify the expression. Remove all negative and zero exponents. Assume the expression is defined. $\left( \frac { \mathrm { c } } { \mathrm { gf } } \right) ^ { - 1 }$

A) $\frac { \mathrm { cg } } { \mathrm { f } }$
B) $\frac { \mathrm { c } } { \mathrm { gf } }$
C) $\frac { g } { c f }$
D) $\frac { \mathrm { gf } } { \mathrm { c } }$
E) $\frac { \mathrm { cg } } { \mathrm { f } }$