Factor Completely $x^{2}-16 x+64$ A) $(x-4)^{2}$ B) $(x+8)^{2}$ C) $(x-8)^{2}$ D) Prime

Factor completely. If the polynomial cannot be factored, write "prime."
- $x^{2}-16 x+64$

A) $(x-4) ^{2}$
B) $(x+8) ^{2}$
C) $(x-8) ^{2}$
D) prime