Choose the option that correctly matches the organism with its characteristics.

Obelia (Cnidaria) -Diploblastic. Obelia shows metagenesis during life cycle. It alternates between polyp and medusa stages.Liver fluke (Platyhelminthes) - Flame cells are primarily osmoregulatory and secondarily excretory in function. It has a sucker but not hooks.Ctenoplana (Ctenophora)  - Marine and has no muscular foot (Muscular foot is observed in Mollusca).Spongilla - Fresh water sponge (Euspongia is the bath sponge).