Answer:
B. People face trade-offs
Step-by-step explanation:
Opportunity cost refers to the benefits foregone of a non chosen alternative when another alternative is chosen.
In the given case, time is a scarce resource and is limited. Within the limited time, Juanita can either perform any of the three activities or different combinations of the three activities.
To perform one activity more than others, requires sacrifice of time from other activities which means one can be taken up only at the expense of another. This represents a trade off wherein if one wants more of something, it requires corresponding sacrifice of something else.
Since Juanita's efficiency is not provided in absolute terms i.e measurable terms, the given situation corresponds to a state of a trade off.