The accompanying diagram shows the private marginal cost (MCp) curve (which is also the market supply curve), and the private marginal benefit (MBp ) curve (which is also the demand curve) for a S=MC good. Suppose that for any quantity of output, the good has an external marginal benefit of $25 per unit. The allocationly efficient quantity of output is (Type a whole number.) Price ($) . .. D = MBP 0 10 20 30 40 50 60 70 80 90 100 110 120 Quantity