Decide What Values of the Variable Cannot Possibly Be Solutions $$\frac { 1 } { x - 3 } - \frac { 1 } { x + 7 } = 12$$

Multiple Choice

Decide what values of the variable cannot possibly be solutions for the equation.
- $$\frac { 1 } { x - 3 } - \frac { 1 } { x + 7 } = 12$$

A) $- 7,3$
B) $- \frac { 1 } { 7 } , \frac { 1 } { 3 }$
C) $- 3,7$
D) $- \frac { 1 } { 3 } , \frac { 1 } { 7 }$