Evaluate the Numerical Expression $- 16 ^ { \frac { 1 } { 2 } }$

Multiple Choice

Evaluate the numerical expression. $- 16 ^ { \frac { 1 } { 2 } }$

A) $\frac { 1 } { 4 }$
B) $-$ 8
C) $-$ 4
D) No correct answer defined.