Factor completely: 81x^4 – 1
A(9x + 1)(9x – 1)
B(9x^2 + 1)(9x^2 – 1)
C(3x^2 + 1)^3(3x – 1)
D(9x^2 + 1)(3x + 1)(3x – 1)
A(9x + 1)(9x – 1)
B(9x^2 + 1)(9x^2 – 1)
C(3x^2 + 1)^3(3x – 1)
D(9x^2 + 1)(3x + 1)(3x – 1)