Suppose a monopolist's profit-maximizing output is 200 units per week and that the firm sells its output at a price of $60 per unit. The firm has total costs of $9,000 per week. Assume the monopolist is maximizing its profit and earns $30 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? ES $ c. What is the firm's average total cost?