Find the Exact Value of the Expression $\sin ^ { - 1 } ( 0.5 )$

Find the exact value of the expression.
- $\sin ^ { - 1 } ( 0.5 )$

A) $\frac { \pi } { 6 }$
B) $\frac { 7 \pi } { 3 }$
C) $\frac { \pi } { 3 }$
D) $\frac { 7 \pi } { 6 }$