Over 20 species of fish have descended from a single common ancestral species. Fossil evidence shows that each of these species evolved when fluctuating water levels totally isolated small sub-populations of the original ancestral species into several different small lakes and prevented interbreeding. Today they are all completely sympatric (all live in the same large lake.) We can identify them all accurately by their morphology. With this evidence, how best can we hypothesize what type of speciation was involved ? Group of answer choices a. Sympatric speciation b. Phylogenetic speciation c. Allopatric speciation d. Phenetic speciation