A researcher conducts a simple experiment to study the endowment effect. Here is how the experiment works. A group of students is brought into a research lab, and they are randomly divided into two smaller subgroups. The first subgroup is given an insulated water bottle. This subgroup is then asked to state the lowest price at which they'd be willing to sell their newly acquired water bottle (we'll refer to this price as the selling price). The subgroup that did not get a water bottle is then asked to state the most that they would be willing to pay to buy a water bottle (we'll refer to this price as the buying price). Suppose this experiment is conducted three times on three groups of students. In student group A, the reported selling price is $13.76, and the reported buying price is $19.04. In student group B, the reported selling price is $15.04, and the reported buying price is $15.20. In student group C, the reported selling price is $20.48, and the reported buying price is $12.32. Which group (or groups) show signs of the endowment effect