Find the Domain of the Rational Function $$f ( x ) = \frac { x ^ { 2 } - 9 } { x ^ { 2 } - 8 x + 12 }$$

Multiple Choice

Find the domain of the rational function.
- $$f ( x ) = \frac { x ^ { 2 } - 9 } { x ^ { 2 } - 8 x + 12 }$$

A) domain of $f : ( \infty , - 3 ) \cup ( - 3,3 ) \cup ( 3 , \infty )$
B) domain of $f : ( \infty , 0 ) \cup ( 0 , \infty )$
C) domain of $f : ( \infty , 2 ) \cup ( 2,6 ) \cup ( 6 , \infty )$
D) domain of $f : ( \infty , - 6 ) \cup ( - 6 , - 2 ) \cup ( - 2 , \infty )$