Multiply these polynomials.

(5x2 + 2x)(3x2 - 7x + 4)

A. 15x4 - 29x3 + 20x2 + 8x
B. 15x4 - 35x3 + 6x2 + 8x
C. 15x4 - 29x3 + 6x2 + 8x
D. 15x4 - 35x3 + 20x2 + 8x