Simplify the Rational Expression $\frac { a ^ { 2 } - a b + 12 a - 12 b } { a + 12 }$

Multiple Choice

Simplify the rational expression.
- $\frac { a ^ { 2 } - a b + 12 a - 12 b } { a + 12 }$

A) $\frac { a ^ { 2 } - a b + 12 a - 12 b } { a + 12 }$
B) $a - 2 b + 1$
C) a - b
D) $\frac { 1 } { a + 12 }$