Use Rational Exponents to Simplify the Following $\sqrt [ 16 ] { ( x + 7 ) ^ { 4 } }$

Multiple Choice

Use rational exponents to simplify the following.
- $\sqrt [ 16 ] { ( x + 7 ) ^ { 4 } }$

A) $( x + 7 ) ^ { 1 / 4 }$
B) $x ^ { 4 } + 7 ^ { 4 }$
C) $( x + 7 ) ^ { 4 }$
D) $x ^ { 1 / 4 } + 7 ^ { 1 / 4 }$