Factor completely x^8-16

A.) (x^4 - 4) ( x^4 + 4)

B.) ( x^2 - 2) ( x^2 + 2) (x^4+4)

C.) (x^2 - 2) (x^2 + 2) (x^4-4)

D.) (x^2-2) (x^2-2) (x^4-4)