Final answer:
Hourly workers, such as bartenders and servers, may often earn more than their supervisors due to the variability in working hours and tips, which can be substantial and augmented by working during high-tipping periods or overtime shifts. The correct answer is a).
Step-by-step explanation:
The question asks why it is not uncommon for hourly workers, such as bartenders and serving personnel, to take home more pay than their supervisors. The correct answer is a) Variability in working hours and tips. This reflects the economic reality that part-time and full-time workers have different responses to wage changes, as mentioned in the provided reference material. Hourly workers in sectors like hospitality can often earn additional income through tips, which can be substantial and lead to earnings that exceed their supervisors' salaries, who might not receive tips. Moreover, such workers may adjust their working hours to take advantage of higher tip-earning shifts or events, further increasing their income.
Another aspect to consider is overtime opportunities. Hourly workers who put in extra hours could be earning overtime pay, which is typically higher than regular hourly wages and can contribute to their higher take-home pay. However, within the context of this question, the most direct factor resulting in hourly workers earning more would be 'a) Variability in working hours and tips' as this directly influences their immediate income levels.