Figuer: Main Animal Groups Are Noted at the Right. Names Diverging

Figuer:
Main animal groups are noted at the right. Names diverging at each node are morphological or body form names. Note that the animal traits key to distinguishing the groups and body forms are not shown.
-The distinguishing animal trait "A," that separates the body forms of the Eumetazoa and the Parazoa is

A) whether it is the mouth or the anus which forms first from the opening in the developing embryo.
B) whether or not the animal has true tissues.
C) whether the animal must periodically molt in order to grow, or has characteristic soft larval stages.
D) whether the animal has bilateral symmetry and three germ layers, or radial symmetry and two germ layers.
E) None of these answer options is correct.