b. A profit-maximizing firm in a competitive market is currently producing 100 units of output. It has average revenue of f10, average total costs of E8 and fixed costs of 1200. What is the firm's: (i) Profit? (7.5 marks) (ii) Marginal cost? (7.5 marks) (iii) Average variable cost? (7.5 marks) (iv) Is the efficient scale of the firm more than, less than, or exactly 100 units? (7.5 marks)