Animals in which the body cavity is not completely lined with mesoderm are called pseudocoelomates. Nematodes (roundworms) and rotifers are pseudocoelomates. Enterobius (roundworm), Wuchereria, Ancylostoma (hookworm), Dracunculus, and Ancylostoma (hookworm) are nematodes with pseudocoelom. Turbellaria and Taenia belong to phylum Platyhelminthes which are triploblastic with a solid body and no body cavity i.e. they are acoelomates. Thus, the correct answer is option A.