Write the Expression in Exponential Form $\sqrt [ 9 ] { 2 x + 5 y }$

Multiple Choice

Write the expression in exponential form. Assume that all variables represent positive real numbers.
- $\sqrt [ 9 ] { 2 x + 5 y }$

A) $( 2 x + 5 y ) ^ { 1 / 9 }$
B) $\left( \frac { 2 } { 3 } x + \frac { 5 } { 3 } y \right) ^ { 1 / 3 }$
C) $( 2 x + 5 y ) ^ { 1 / 3 }$
D) $( 2 x + 5 y ) ^ { 3 }$