Marginal benefit vs Marginal Cost

As a result of a production quota set below the equilibrium quantity : marginal benefit will exceed marginal cost. Why?

The marginal benefit to the firm is the price paid for the last unit produced. The equilibrium quantity has marginal benefit = marginal cost, and less production than the equilibrium quantity means that the cost is lower (diminishing returns) than what people are willing to pay. Supply/demand curve, brother.