6. scarcity, opportunity cost, and marginal analysis clancy is training for a biathlon, a winter racing sport that combines cross-country skiing and rifle shooting. consider the following scenario: in order to ski for one hour, clancy must take that time off of work, where he earns an hourly wage of $19. additionally, there is a $8 entrance fee to the skiing facility. which basic principle of individual choice do these statements best illustrate? markets are usually a good way to organize economic activity. people usually exploit opportunities to make themselves better off. the cost of something is what you give up to get it. trade can make everyone better off.