Write in Radical Form $$( 9 m + n ) ^ { 3 / 4 }$$

Multiple Choice

Write in radical form. Assume all variables represent positive real numbers.
- $$( 9 m + n ) ^ { 3 / 4 }$$

A) $\sqrt [ 4 ] { ( 9 m + n ) ^ { 3 } }$
B) $\sqrt [ 4 ] { 9 m + n ^ { 3 } }$
C) $\sqrt [ 3 ] { ( 9 m + n ) ^ { 4 } }$
D) $\sqrt [ 3 ] { 9 m + n ^ { 4 } }$