Flatworms Differ from Cnidarians in That Flatworms

Flatworms differ from cnidarians in that flatworms

A) are radially symmetrical, whereas cnidarians are bilaterally symmetrical.
B) have more complex internal organs than cnidarians do.
C) are diploblastic, whereas cnidarians are triploblastic.
D) have two openings to the digestive cavity, whereas cnidarians have only one.
E) have an excretory system, whereas cnidarians do not.