Which of the Following Statements Would Be Least Acceptable to Most

Which of the following statements would be least acceptable to most zoologists?

A) The extant cephalochordates (lancelets) are contemporaries, not ancestors, of vertebrates.
B) The first fossils resembling cephalochordates appeared in the fossil record around 550 million years ago.
C) Recent work in molecular systematics supports the hypothesis that cephalochordates are the most recent common ancestor of all vertebrates.
D) The extant cephalochordates are the immediate ancestors of the fishes.
E) Cephalochordates display the same method of swimming as do fishes.