The only two brewers in a small town compete in the following game. First Alacrity Ales brews, which decides the quantity of beer that Alacrity will be able to sell. Brown Beer knows how much Alacrity brewed and then brews their batch, determining how much beer Brown will be able to sell. Costs are C_A =q^2_A and C_B=q^2_B while the demand for locally brewed beer is D=16-P . If Alacrity brews q_A=4, what quantity maximizes B's profit?