Assume that in a particular industry the minimum efficient scale of operations is​ 6,000 units of output. That​ is, the long run ​("Uminus ​shaped") average cost curve reflects a minimum efficient scale at​ 6,000 units of output. If that is the​ case, we would most likely expect that the industry would be A. an oligopoly if the fourminus firm concentration ratio is more than 10 percent. B. an oligopoly if the market quantity demanded is​ 18,000 units. C. perfectly competitive if the market quantity demanded is​ 20,000 units. D. monopolistically competitive if the market quantity demanded is​ 12,000 units.