MC ATC Price and costs (dollars) MR 00 4 o 90 130 170 210 Quantity (units per day) The figure above shows the marginal revenue and costs of a perfectly competitive firm. When 170 units are produced, the Select one: O a. firm's total costs are less than $2,720. b. All of the above are true. O c.firm is making an economic profit. O d. firm has total revenue of $2,720