The correct option is D Ancylostoma
Taenia is a genus of tapeworm and it belongs to Platyhelminth.
Echinococcus is a cyclophyllid cestode that parasitizes in the small intestine of canids and it belongs to Platyhelminth.
Fasciola is a genus of trematodes and it belongs to Platyhelminth.
Ancylostoma is a genus that includes some species of hookworm so it is a nematode.
So, the correct answer is option D.