Evaluate the Function at the Indicated Value Of $x = 3$

Evaluate the function at the indicated value of $x = 3$ . ​​ $f ( x ) = \log _ { 243 } x$ ​

A) $\frac { 1 } { 5 }$
B) -5
C) $- \frac { 1 } { 5 }$
D) 0
E) 5