This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Protozoa, Subject name: Microbiology
[{'content': 'Largest protozoan is? \nSelect and explain. \nA. E. Histolytica, B. Balantidium coli, C. E.coli, D. Plasmodium', 'role': 'user'}, {'content': 'Answer: B \nExplanation: ANSWER: (B) Balantidium coliREF: Jawett\'s 24th edition Section VI. Parasitology > Chapter 46-Medical Parasitology"Balantidium coli, the cause of balantidiasis or balantidial dysentery, is the largest intestinal protozoan of humans"', 'role': 'assistant'}]