Factor Out the GCF from the Polynomial $7 a ( a - b ) + ( a - b )$

Multiple Choice

Factor out the GCF from the polynomial.
- $7 a ( a - b ) + ( a - b )$

A) $7 a ( a - b )$
B) $8 a ( a - b )$
C) $\left( 7 a ^ { 2 } - 7 a b \right) + ( a - b )$
D) $( a - b ) ( 7 a + 1 )$