Suppose a monopolist's profit-maximizing output is 400 units per week and that the firm sells its output at a price of $100 per unit. The firm has total costs of $8,000 per week. Assume the monopolist is maximizing its profit and earns $50 per unit from the sale of the last unit produced each week Instructions: Enter your answers as a whole number a. What are the firm's weekly economic profits? b. What is the firm's marginal cost? $ c. What is the firm's average total cost? $