Simplify $- \sqrt [ 4 ] { 16 m ^ { 24 } }$

Multiple Choice

Simplify $- \sqrt [ 4 ] { 16 m ^ { 24 } }$ . Assume all variables represent positive real numbers.

A) $- 2 m ^ { 6 }$
B) $- 4 m ^ { 6 }$
C) $- 4 m ^ { 12 }$
D) not a real number