Final answer:
A person will decide to take a day off work when the marginal cost of doing so is less than the marginal benefit, applying the concept of marginal analysis which includes assessing additional costs and benefits of an action.
Step-by-step explanation:
A person will decide to take the day off work if the marginal cost is less than the marginal benefit. This decision-making process involves considering the additional cost and benefit of one more unit of an action, in this case, taking a day off work. Using the principle of marginal analysis, a tool economists use to make the most productive or beneficial decisions, an individual assesses whether the benefits of having a day off (like rest or personal time) outweigh the costs (like lost wages or work piling up).
Considering the example of Alphonso and his bus tickets: Alphonso will buy more bus tickets only as long as the marginal utility of the tickets exceeds the marginal cost, which is the utility of what he has to give up—in this case, burgers. Once the opportunity cost exceeds the marginal utility of the bus tickets, Alphonso will stop purchasing them.
In terms of the given choices, the correct answer to when a person will decide to take the day off work is choice a) when the marginal cost is less than the marginal benefit.