(1) (2) (3) firm quantity average total cost A 200 units $5 B 400 units $4 600 units $7 in exhibit 12 above, the resource-allocationficient output is 600 units. currently, firm B is the only firm supplying the good; it is supplying 400 units. based on the data presented in exhibit 12, is firm B a natural monopoly? if so why? O no, because firm A can supply 200 units at a lower average total cost thatn firm B can supply 400 units. O no, because it is not the only firm than can supply the good yes, because it can supply the entire output O no, because it cannot supply the entire output (600) units at lower cost ($4,200) than the two firms together (where firm A produces 200 units at $5 per unit and firm B produces 400 units at $4 per unit)