ACT Problem 27

$$\begin{array}{lcl} 27.\;What\;is\;the\;product\;of\;the\;polynomials\\ ab+a^2b^3\;and\;a^2b^3-ab?\\ \\ (A)\; a^4b^6-2a^3b^4+a^2b^2\\\\ (B)\; a^4b^6+2a^3b^4+a^2b^2\\\\ (C)\; a^4b^6-a^2b^2\\\\ (D)\; a^4b^6+a^2b^2\\\\ (E)\; -a^4b^6-a^2b^2\\ \end{array}$$