Which one of the following statements about all the four of Spongilla, leech, dolphin and penguin is correct?

Spongilla belongs to phylum-Porifera, in which, choanoytes are the characteristic cells, these are absent in leech, dolphin and pengiun. These distinctive cells line the interior body walls of sponges. These cells have a central flagellum that is surrounded by a collar of micovilli. Choanocytes are versatile cells. Their flagella beat to create the active pumping of water through the sponge, while the collars of the choanocytes are the primary areas where nutrients are absorbed into the sponge.