Afirm has three different production facilities, all of which produce the same product. while reviewing the firm's cost data, jasmin, a manager, discovers that one of the plants has a higher average cost than the other plants and suggests closing that plant. another manager, joshua, notes that the high-cost plant has high fixed costs but that the marginal cost for that plant is lower than in the other plants. he says that the high-cost plant should not be shut down but should expand its operations. who is right?