Rewrite Without Rational Exponents, and Simplify, If Possible $(\mathrm{mn})^{1 / 4}$

Multiple Choice

Rewrite without rational exponents, and simplify, if possible.
- $(\mathrm{mn}) ^{1 / 4}$

A) $(\mathrm{mn}) ^{-4}$
B) $\sqrt{(\mathrm{mn}) ^{4}}$
C) $\frac{1}{\sqrt[4]{\mathrm{mn}}}$
D) $\sqrt[4]{\mathrm{mn}}$