Cephalization is clearly adaptive for the free-living planarians that must locate their food; why would the parasitic flukes and tapeworms retain cephalization?

A)Those with separate sexes would need to locate one another when mating.
B)Parasitic infection is typically organ specific; parasites need to sense their location before attaching to a body structure.
C)Parasite life cycles require dispersal to new hosts, some parasites actively sense potential hosts and move toward them.
D)All of the above are reasonable hypotheses.