As recently as the 1990s, the evolutionary history of whales remained unclear. Scientists didn’t know if whales were descended from a now extinct carnivore (mesonychids) or if they were more closely related to modern hoofed mammals like ruminants (e. g., cows and deer) and hippos. The phylogenies below represent these two possible histories. If you were a scientist looking to find support for the theory that hippos are more closely related to whales than to mesonychids, which of the following would potentially provide the strongest piece of evidence in support of phylogeny "B"?
a. The discovery that hippos and whales have very similar courtship behavior.
b. The discovery that ruminants (such as cows and deer) are more closely related to hippos than previously thought.
c. The discovery that ancient whales share a defining characteristic with modern ruminants and hippos.