the question

Consider a vertically related market. Demand for the final product is given by P= a- 6Q. A manufacturer sells a product to two downstream retailers. The retailers sell to the consumer. The two retailers sell homogeneous products. The manufacturer and the retailers all have zero production costs. The timing of the game is that at the wholesale stage, the manufacturer sets a contract. After observing the contract, at the retail stage, the two retailers compete in the final product market. In all the cases below, we consider the subgame perfect equilibrium. Case 1: The manufacturer sets a wholesale price w. The two retailers compete by setting prices simultaneously. Case 2: The manufacturer sets a wholesale price w. The two retailers compete by setting quantities simultaneously. Case 3: The manufacturer sets a two-part tariff {w, F}, where wis a per-unit charge and Fis a fixed fee. The retailers compete by setting prices simultaneously. Which of the following statements is/are correct? (J a. The consumer surplus in Case 3 is strictly higher than the consumer surplus in Case 2. _) b. The total surplus in Case 2 is strictly higher than the total surplus in Case 3. (| ce. Consumers are strictly better off in Case 1 than in Case 2. (1 d. The total surplus in Case 3 is strictly higher than the total surplus in Case 1