Table 4-4 Price Quantity Supplied (Dollars per unit) (Units) Firm A Firm B Firm C Firm D 0 0 0 0 NO 2 3 4 5 4 4 6 8 10 6 6 9 12 15 8 12 14 20 10 10 15 16 25 Refer to Table 4-4. If these are the only four sellers in the market, then when the price decreases from $8 to $6, the market quantity supplied O a. decreases by 20 units. O b. decreases by 42 units. O c. decreases by 12 units. O d. increases by 33 units