Find All Values That Make the Rational Expression Undefined $$\frac { a - 3 } { 7 - a }$$

Multiple Choice

Find all values that make the rational expression undefined. If the rational expression is defined for all real numbers, so
state.
- $$\frac { a - 3 } { 7 - a }$$

A) $a = 7 , a = 3$
B) $a = 7$
C) $a = - 7$
D) Defined for all real numbers