The correct option is D Pila, Dentalium, octopus
Ascaris is in Nemathelminthes. Pheretima is in Annelida. Grasshopper is Arthropoda.
Hydra is coelenterate. Teredo is mollusc. Leucosolenia is Porifera.
Starfish is echinoderm, grasshopper is Arthropoda, Solen is mollusc.
Pila, Dentalium and octopus are molluscs. Hence, option D is correct answer.