Evaluate the Expression $\left( \frac { 16 } { 25 } \right) ^ { - 1 / 2 }$

Multiple Choice

Evaluate the expression.
- $\left( \frac { 16 } { 25 } \right) ^ { - 1 / 2 }$

A) $\frac { 8 } { 25 }$
B) not a real number
C) $\frac { 5 } { 4 }$
D) $\frac { 4 } { 5 }$