Write the Expression in Exponential Form $\sqrt [ 6 ] { x }$

Multiple Choice

Write the expression in exponential form. Assume that all variables represent positive real numbers.
- $\sqrt [ 6 ] { x }$

A) $x ^ { - 1 / 3 }$
B) $x ^ { - 3 }$
C) $x ^ { 3 }$
D) $\mathrm { x } ^ { 1 / 3 }$