Why Is It Thought That Certain Primitive Fish Diverged from Vertebrates

Multiple Choice

Why is it thought that certain primitive fish diverged from vertebrates before the globin gene was first duplicated?

A) The fish are very old.
B) The fish do not have any hemoglobin.
C) The hemoglobin of the fish consists of 8 polypeptide subunits.
D) These fish have only one globin gene instead of multiple globin genes, suggesting that they diverged from other vertebrates before the first duplication of the globin gene.
E) These fish have four globin genes instead of a single globin gene, suggesting they diverged from other vertebrates before the first duplication of the globin gene.