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Question 17 (4 marks) Which of the following is always upward-sloping? a. The marginal cost curve when it is below the average total cost curve. b. The marginal cost curve when it is above the average total cost curve. C. The average fixed cost curve when it is below the marginal cost curve. d. The average total cost curve when it is above the marginal cost curve. Question 20 (4 marks) It was reported that General Motors planned to essentially quit making cars and trucks in the United States for nine weeks from mid-May through July 2009 and Omaha Power planned to close one of its nuclear plants permanently. Based on these particular news reports, what is the difference between GM's and Omaha Power's decisions? a. Omaha Power was trying to get rid of excess inventory, and GM was trying to become more efficient. b. GM was trying to maximise profits while Omaha Power was trying to minimise losses. c. GM's decision to idle plants was a short-run shutdown decision. Omaha Power, by contrast, made a long-run decision to exit a specific market. d. There is no difference between GM's and Omaha Power's decisions; both were trying to get rid of excess inventory