Factor the Perfect Square Trinomial Below $x ^ { 2 } + 18 x + 81$

Multiple Choice

Factor the perfect square trinomial below. $x ^ { 2 } + 18 x + 81$

A) $( x + 18 ) ^ { 2 }$
B) $( x - 18 ) ^ { 2 }$
C) $( x + 9 ) ( x - 9 )$
D) $( x + 9 ) ^ { 2 }$
E) $( x - 9 ) ^ { 2 }$