문 17. Excellence is the absolute prerequisite in fine dining because the prices charged are necessarily high. An operator may do everything possible to make the restaurant efficient, but the guests still expect careful, personal service: food prepared to order by highly skilled chefs and delivered by expert servers. Because this service is, quite literally, manual labor, only marginal improvements in productivity are possible. For example, a cook, server, or bartender can move only so much faster before she or he reaches the limits of human performance. Thus, only moderate savings are possible through improved efficiency, which makes an escalation of prices _______. (It is an axiom of economics that as prices rise, consumers become more discriminating.) Thus, the clientele of the fine-dining restaurant expects, demands, and is willing to pay for excellence. 

③ preposterous (공)

④ inconceivable (수)