4. To reach maximum profit in a competitive market, producers should expand production until a. Maximum revenue has been generated b. Marginal cost is at its lowest point c. Increasing marginal costs reach the price d. Diminishing returns yield maximum costs 5. The marginal cost is a. The change in total revenue divided by the change in output b. The cost of producing one additional item c. Always less than the price d. All of the above e. None of the above 6. If one firm controls all of the supply in a market, this is called a. Duopoly b. Monopoly c. Oligopoly d. Perfect competition 7. My telephone bill has the following charges: Monthly access fee = $5.00 100 Calls at $. 12 per call Fixed cost Variable Cost Total cost