Penguins, Seals, and Tuna Have Body Forms That Permit Rapid

Penguins, seals, and tuna have body forms that permit rapid swimming, because ________.

A) all share a recent common ancestor
B) all of their bodies have been compressed since birth by intensive underwater pressures
C) the shape is a convergent evolutionary solution, which reduces drag while swimming
D) this is the only shape that will allow them to maintain a constant body temperature in water