Which of the following involves thinking at the margin? Group of answer choices A group of kids decides to go to one more house to trick-or-treat. A scientist decides to apply for a large grant to fund her research. A college senior decides to attend graduate school for two years. The school board decides to extend the mask mandate for six months.

Thinking at the margin involves making decisions based on the additional benefit or cost of a specific action. In this scenario, the group of kids is considering whether to visit one more house to trick-or-treat. By thinking at the margin, they are weighing the additional benefit of potentially getting more candy against the cost of their time and effort. They are making a decision based on the incremental gain or loss they expect from their choice. This aligns with the concept of thinking at the margin, as they are evaluating the marginal benefit of one more house visit.