Convert the Expression to Radical Notation $16 z ^ { 4 / 7 }$

Multiple Choice

Convert the expression to radical notation. $16 z ^ { 4 / 7 }$

A) $\sqrt [ 7 ] { ( 16 z ) ^ { 4 } }$
B) $\sqrt [ 7 ] { 16 z ^ { 4 } }$
C) $16 \sqrt [ 7 ] { z ^ { 4 } }$
D) $16 \sqrt [ 4 ] { z ^ { 7 } }$