The paths three motorcyclists took on an afternoon ride are shown. Riders A and C traveled from the coffee shop to the mechanic's garage along different paths, while Rider B traveled from the garage to the coffee shop. Three physics students discussing these rides make the following contentions; Ali: "The lengths of the paths that Riders A and B travel are the same, so they have the same displacement. Rider C has the smallest displacement." Bob: "I agree that Rider C has the smallest displacement because the diagonal path is shortest. But the displacements of Riders A and B are actually different because their directions are opposite each other." Carol: "I think the displacements of all three riders are the same, because they go between the same two points. What path they follow doesn't matter." Which student is correct and why?

Coffee Shop 4 km Rider A 5 km Rider C 3 km Rider B Garage