This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: parasitology, Subject name: Microbiology
[{'content': 'Saturated salt solution concentrates eggs of all, except- \nSelect and explain. \nA. Unfeilized egg of ascaris, B. Trichuris, C. Hymenolepsis nana, D. Enterobius vermicularis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Helminth eggs floating in saturated salt solution: Hell FATE Hell-Helminth,H.nana F-Feilised eggs of Ascaris A-Ancylostoma duodenale T-Trichuris trichiura E-Enterobius vermicularis', 'role': 'assistant'}]