Find the Function Value $f ( x ) = 3 ^ { x }$

Multiple Choice

Find the function value. If the result is irrational, round your answer to the nearest thousandth.
-Let $f ( x ) = 3 ^ { x }$ . Find $f ( - 2 )$

A) $- 6$
B) $\frac { 1 } { 9 }$
C) $\frac { 1 } { 8 }$
D) $- \frac { 1 } { 6 }$