There are four consumers willing to pay the following amounts for haircuts, and there are four haircutting businesses with the following costs: Consumers' Willingness to Pay Shen: $35 Manuel: $50 Poornima: $40 Valerie: $25 Firms' Costs Firm A: $25 Firm B: $40 Firm C: $30 Firm D: $45 Each firm has the capacity to produce only one haircut. For efficiency, should be given.