Cnidarians Have a Gastrovascular Cavity Rather Than a Complete Gut;

Cnidarians have a gastrovascular cavity rather than a complete gut; in what way(s) would this arrangement be less functional?

A) A blind-ended cavity increases the probability of parasite attachment within the cavity.
B) Gastrovascular digestion is less efficient because the more powerful digestive chemicals seen in advanced animals, like stomach acids, would be destructive with this type of organization.
C) Lacking a mouth and the capacity for chewing greatly reduces the potential prey items available for cnidarians in comparison to other animals.
D) Because undigestible materials must pass out through the same opening used to enter the cavity, a single item must be completely digested and expelled before digestion of a new food item can begin.