This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'A patient presents with diarrhea. analysis of stool on wet mount shows mobile protozoa without RBCs and pus cells. The diagnosis is \nSelect and explain. \nA. Balantidium coli, B. Giardiasis, C. Trichomonas hominis, D. Entamoeba histolytica', 'role': 'user'}, {'content': "Answer: B \nExplanation: Mobile protozoa with the absence of RBC's and pus cells in stools in a patient with diarrhoea suggests giardiasis.\nIn balantidium coli and entamoeba histolytica infections, pus cells and RBC's will be present in stools.\nTrichomonas hominis is considered as non-pathogenic", 'role': 'assistant'}]