Which of the following statements is correct with respect to the evolutionary relationship between chordates and invertebrates?
A. chordates are most closely related to arthropods
B. chordates are more closely related to echinoderms than to arthropods
C. chordates are most closely related to the tunicate-type of echinoderms
D. chordates evolved from echinoderms
Please explain why the correct answer is B, and why A is incorrect