Let $f ( x ) = \frac { x + 1 } { x ^ { 2 } - 1 }$

Multiple Choice

Let $f ( x ) = \frac { x + 1 } { x ^ { 2 } - 1 }$ Which of the following is true?

A) ƒ is defined at 1.
B) ƒ is defined at -1.
C) ƒ has a removable discontinuity at -1.
D) ƒ has a removable discontinuity at 1.
E) ƒ is continuous at -1.