The Diagram Below Represents the Ranges of Three Closely Related

The diagram below represents the ranges of three closely related species (A, B, and
C), which are separated by a mountain range and river. As an expert geologist, you hypothesize that the area was originally occupied by a single species. Its range was split first by the mountain range. Later, the river formed, separating populations on the eastern side of the mountains. If your hypothesis is correct, what should the phylogenetic relationships be among the three species? Draw a phylogeny as your answer.