Which equation shows p(x)= x^6 - 1 factored completely over the integers? (Hint : You will need to use more than one method to complete this problem.)
A. p(x)= ( x - 1 ) ( x^2 + x + 1) ( x + 1 ) ( x^2 - x + 1 )
B. p(x)= ( x^3 - 1 ) ( x^3 - 1 )
C. p(x)= ( x^2 - 1 ) ( x^4 + x^2 + 1 )
D. p(x)= ( x - 1 ) ( x + 1 ) ( x^4 + x^2 + 1 )