Factor 20x^3 - 25x^2 + 4x - 5

a) (5x^2 - 5)(4x + 1)
b) 5(x^2 - 1)(4x + 5)
c) (5x^2 + 1)(4x - 5)
d) (5x^2 + 1)(4x - 1)

The correct factorization is d) (5x^2 + 1)(4x - 1)