1 1. The most efficient output is found (LO3) a) where MC and MR cross b at the bottom of the ATC curve c) when the demand and MR curves are equal d) where the ATC and demand curves cross 12. When the monopolist is losing money, (LO3) we are in the short run we are in the long run it is impossible to tell if we are in the short run or the long run d) we have to go back and check our work because monopolists don't lose money