Quick pre calculus question for 10 easy points

Please only answer if you know for sure.. And I need to show my work -_-

Write f(x)=x^3-4x^2+4x-16 as a product of linear factors.

You can factor this one by grouping

f(x) = x^3 - 4x^2 + 4x - 16

f(x) = x^3 + 4x - 4x^2 - 16

f(x) = x(x^2 + 4) - 4(x^2 + 4)

f(x) = (x^2 + 4)(x - 4)

f(x) = (x + 2i)(x - 2i)(x - 4)

f(x) = x^2(x-4)+4(x-4)
f(x) = (x-4)(x^2+4)
Can only be expressed in linear factors using complex numbers
f(x) = (x-4)(x+2i)(x-2i)