Which Statement About the Vertebrates Is Most Accurate

Which statement about the vertebrates is most accurate?

A) They are the dominant phylum in the animal kingdom.
B) There are more vertebrate species than flatworms or cnidarians but fewer than there are insects.
C) They are the only group to have evolved aquatic, terrestrial, and flying lifestyles.
D) They evolved from echinoderms.
E) They evolved from molluscs.