What is the answer and why?

20. Quantity Price Supplied (P) (Qs) MSC MSC MSC. $20 MSC3 5.00 $2.00 $10 $30 $20 26 7.00 2.60 16 36 26 28 7.67 2.80 18 38 28 32 9.00 3.20 22 42 32 36 10.33 3.60 26 46 36 38 1 1.00 3.80 28 48 38 Table: The Marginal Social Cost of Batteries The table lists several price (P) and quantity (Os) values along the market supply curve for batteries. Because batteries generate toxic wastes, there is an external cost associated with their production. The marginal external cost is estimated to be $10. The marginal social cost would then be indicated by the values in the column labeled: a. MSC1. b. MSC2. C. MSC3. d. Price (P) . MSC4