Rationalize the Denominator and Simplify $\sqrt [ 4 ] { \frac { 81 } { 8 } }$

Multiple Choice

Rationalize the denominator and simplify. Assume that all variables represent positive real numbers.
- $\sqrt [ 4 ] { \frac { 81 } { 8 } }$

A) $\frac { 3 \sqrt { 2 } } { 2 }$
B) $\frac { 3 \sqrt { 8 } } { 8 }$
C) $\frac { 3 \sqrt [ 4 ] { 2 } } { 2 }$
D) $\frac { 3 \sqrt { 8 } } { 2 }$