Use Rational Exponents to Simplify $\sqrt [ 6 ] { 216 }$

Multiple Choice

Use rational exponents to simplify. Assume that all variables represent positive real numbers.
- $\sqrt [ 6 ] { 216 }$

A) $6 \sqrt { 6 }$
B) $\sqrt [ 3 ] { 6 }$
C) $\sqrt { 6 }$
D) $\frac { 1 } { 36 }$