The correct option is A Liver fluke
∙ Liver flukes belong to phylum Platyhelminthes. The animals that belong to Platyhelminthes have a bilaterally symmetrical body, are triploblastic and are either free-living or parasitic. They are flattened dorsiventrally.
∙ Spongilla belongs to phylum Porifera whereas earthworm and leech belong to the phylum Annelida.