able 14-12

Quantity	Long-Run Total Cost(Dollars) Firm 1 Firm 2 Firm 3 Firm 4
1	180	120	150	210
2	350	250	300	340
3	510	390	450	490
4	660	540	600	660
5	800	700	750	850
6	930	870	900	1,060
7	1,050	1,050	1,050	1,290

Refer to Table 14-12. Firm 4's efficient scale occurs at what quantity?

a. 4

b. 3

c. 2

d. 5