Of the following descriptions of migrating animals, which most strongly suggests that the animals are depending on magnetic cues to orient themselves? A. Pigeons can properly readjust their course even when flying long distances through exceedingly dense fogs. B. Bison are able to reach their destination by passing through a landscape that has been partially altered by a recent fire. C. Elephants are able to find grounds that some members of the herd have never seen before. D. Swallows are able to return to a given spot at the same time every year. E. Monarch butterflies coming from different parts of North America are able to arrive at the same location each winter.