The answer is A. Scarcity
In the economic field, scarcity is identified as a condition of limited resources, in which case society lacks sufficient resources to produce enough and by doing so, it cannot satisfy subjective wants. Thus, not every goal of society can be accomplished at the same time, so there has to be a priorization of goods.
In this case, Katherine lacks sufficient time, and has to priorize its use either for cheerleading or studying.
