Table 18-4 Only two firms, ABC and XYZ, sell a particular product. The following table shows the demand curve for their product. Each firm has the same constant marginal cost of $8 and zero fixed cost. Price (Dollars per unit) Quantity Demanded (Units) Total Revenue (Dollars) 28 0 0 26 5 130 24 10 240 22 15 330 20 20 400 18 25 450 16 30 480 14 35 490 12 40 480 10 45 450 8 50 400 6 55 330 4 60 240 2 65 130 0 70 0 Refer to Table 18-4. What is the socially efficient quantity of the product? a. 35 b. 70 c. 25 d. 50