Compute the Exact Value of the Function for the Given $$f ( x ) = 5 ^ { x } \text { for } x = - 1$$

Compute the exact value of the function for the given x-value without using a calculator.
- $$f ( x ) = 5 ^ { x } \text { for } x = - 1$$

A) $\frac { 1 } { 1 }$
B) $- 5$
C) $\frac { 1 } { 5 }$
D) $- \frac { 1 } { 5 }$