Lucia is training for a triathlon, a timed race that combines swimming, biking, and running. Consider the following sentence: Lucia has only 20 hours this week that she can devote to training. Each hour she spends swimming is an hour that she can't spend biking or running. Which basic principle of individual choice do these statements best illustrate? People usually exploit opportunities to make themselves better off. People face trade-offs. Lucia has an incentive to spend more time on swimming than on biking or running. Lucia can use time most efficiently by spending the same amounts of time on swimming, biking, and running.

Answer: People face trade-offs so for we to be the best in some aspect, we ghave to sacrifice some extra time to be best in a specific aspect. this is better than failing in all aspect. dedication to one pact more is not negligence of the other parts but so as to attain perfection at least at one aspect.

If Lucia decides to swim, she forgoes the time that she could have spent biking or running. So the opportunity cost of an hour of swimming is an hour of biking or an hour of running, whichever is the highest-valued alternative must sacrifice in order to spend an additional hour swimming.

There is no information on the effectiveness of an extra hour of swimming as compared to that of an extra hour of biking or running. Therefore, you don't know whether lucia has an incentive to spend more time on swimming.