Factor Completely $21 x ^ { 2 } - 91 x - 70$

Multiple Choice

Factor completely.
- $21 x ^ { 2 } - 91 x - 70$

A) $7 ( 3 x + 2 ) ( x - 5 )$
B) prime
C) $( 21 x + 14 ) ( x - 5 )$
D) $7 ( 3 x - 2 ) ( x + 5 )$