Completely Factor the Polynomial or State That the Polynomial Is $$81 x ^ { 2 } - 16$$

Multiple Choice

Completely factor the polynomial or state that the polynomial is prime.
- $$81 x ^ { 2 } - 16$$

A) $( 9 x + 4 ) ( 9 x - 4 )$
B) $( 81 x + 1 ) ( x - 16 )$
C) $( 9 x + 4 ) ^ { 2 }$
D) $( 9 x - 4 ) ^ { 2 }$