AMS recently instituted an in$-$house recycling program. The benefits of this program include not only the benefits to the environment of recycling but also the goodwill generated by AMS's leadership in this area. The costs of recycling include all of the energy, labor, and space required to do the recycling. Suppose these benefits and costs are given by $B(Q)=100Q-2Q^2$ and $C(Q)=4Q.($Note that $MB=100-4Q,$ and $MC=4.)(5$points$)$

a$.$ What level of $Q$ maximizes the total benefits of recycling?