Table 4-6

Price	Firm A's Quantity Supplied	Firm B's Quantity Supplied	Firm C's Quantity Supplied	Firm D's Quantity Supplied
$0	10	0	0	0
$2	8	3	4	5
$4	6	6	8	10
$6	4	9	12	15
$8	2	12	8	20
$10	0	15	4	25

Refer to Table 4-6. If these are the only four sellers in the market, then the market quantity supplied at a price of $4 is

Group of answer choices

4

7.5

10

30