Simplify the Expression $\left( \frac { r ^ { 4 } r ^ { - 2 } } { r ^ { 4 } r ^ { - 4 } } \right) ^ { 5 }$

Multiple Choice

Simplify the expression. $\left( \frac { r ^ { 4 } r ^ { - 2 } } { r ^ { 4 } r ^ { - 4 } } \right) ^ { 5 }$ Write the answer without using negative exponents. Assume that the variable is restricted to those numbers for which the expression is defined.

A) $r ^ { 10}$
B) $r ^ { 0}$
C) $r ^ { 30}$
D) $r ^ { 5}$