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: Surgery
[{'content': 'In cholangitis, the organism mostly responsible is - \nSelect and explain. \nA. E.Coli, B. Streptococcus, C. E. Histolytica, D. Clostridium', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]