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': 'Which of the following organism is biggest - \nSelect and explain. \nA. Balantidium coli, B. Entamoeba coli, C. Escherichia coli, D. Entamoeba histolytica', 'role': 'user'}, {'content': 'Answer: A \nExplanation: largest protozoal parasite of human Lives in large intestine Two stages- trophozoite and cyst (refer pgno:82 baveja 3 rd edition )', 'role': 'assistant'}]