Required: a. Assume that only one product is being sold in each of the four following case situations: b. Assume that more than one product is being sold in each of the four following case situations. Complete this question by entering your answers in the tabs below. Required A Required B Assume that only one product is being sold in each of the four following case situations: Case 1 Case 2 Case 3 Case 4 Units sold 10,000 20,000 5,000 Sales $ 290,000 $ 378,000 $ 150,000 Variable expenses 200,000 280,000 Fixed expenses 100,000 169,000 83,000 Net operating income (loss)) $ 74,000 $ 82,000 $ (23,000) Contribution margin per unit $ 18 $ 8 Chec