Simplify 2a^2b^3(4a^2 + 3ab^2 - ab)=?
A. 8a^4b^5 + 3a^3b^5 + 2a^3b^4 B.8a^4b^5 + 3a^3b^5 - 2a^3b^4
C.8a^4b^3 + 6a^3b^5 + 2a^3b^4 D.8a^4b^3 + 6a^3b^5 - 2a^3b^4