$\text { Describe the } x \text {-values at which the graph of the function } f ( x ) = \frac { x ^ { 2 } } { x ^ { 2 } - 9 } \text { given below }$

Multiple Choice

$\text { Describe the } x \text {-values at which the graph of the function } f ( x ) = \frac { x ^ { 2 } } { x ^ { 2 } - 9 } \text { given below }$
is differentiable.

A) $f ( x )$ is differentiable at $x = \pm 3$ .
B) $f ( x )$ is differentiable everywhere except at $x = \pm 3$ .
C) $f ( x )$ is differentiable everywhere except at $x = 0$ .
D) $f ( x )$ is differentiable on the interval $( - 2,2 )$ .
E) $f ( x )$ is differentiable on the interval $( 2 , \infty )$ .