What is the difference of the following polynomials?
(6r3 – 2x2 + 4)
- (2x + 4x² – 5)

A)0 4x² – 2x² – 1
B)8x3 + 6x2 - 1
C)4x3 – 2x2 + 1
D)4x3 - 6x2 +9