If $f ( x ) = \frac { x } { x + 6 }$

Multiple Choice

If $f ( x ) = \frac { x } { x + 6 }$ , find $f ( s - 6 )$ .

A) $f ( s - 6 ) = \frac { s - 6 } { s }$
B) $f ( s - 6 ) = \frac { s + 6 } { s + 12 }$
C) $f ( s - 6 ) = \frac { - s - 6 } { s }$
D) $f ( s - 6 ) = \frac { s + 6 } { s }$
E) $f ( s - 6 ) = \frac { s - 6 } { s + 12 }$