6. Scarcity, opportunity cost, and marginal analysis Rosa is training for a triathlon, a timed race that combines swimming, biking, and running. Consider the following sentence: In order to swim for...

Extracted text: 6. Scarcity, opportunity cost, and marginal analysis Rosa is training for a triathlon, a timed race that combines swimming, biking, and running. Consider the following sentence: In order to swim for an hour, Rosa must take time away from work, where she earns $12 per hour. This is in addition to paying a $5 entrance fee for the pool. Which basic principle of individual choice do these statements best illustrate? O The cost of something is what you give up to get it. O Markets are usually a good way to organize economic activity. O People usually exploit opportunities to make themselves better off. O Trade can make everyone better off.