Factor the Polynomial Completely $x ^ { 2 } + 81$

Multiple Choice

Factor the polynomial completely. If the polynomial cannot be factored, write "prime."
- $x ^ { 2 } + 81$

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