If these are the only four sellers in the market, then when the price increases from $4 to $6, the market quantity supplied
Quantity Supplied (Units)
Price (Dollars per unit) Firm A Firm B Firm C Firm D
0 0 0 0 0
2 2 3 4 5
4 4 6 8 10
6 6 9 12 15
8 8 12 14 20
10 10 15 16 25
a. Increases by 28 units
b. Increases by 14 units
c. Decreases by 42 units
d. Increases by 10 units