Answer: C. marginal benefit equals marginal cost.
Explanation:
As is the case in the private sector , the optimal quantity of a public good is the quantity where Marginal benefit (revenue in private) equals marginal cost.
This is the optimal quantity because any quantity made that is more than this will result in marginal cost being greater than marginal benefit. This is therefore the highest quantity that can be produced without costs exceeding benefits so it is optimal.
