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': 'Gas gangrene is/are caused by- \nSelect and explain. \nA. C. novyi, B. C. septicum, C. C. histolyticum, D. All', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'a' i.e., C.novyi 'b' C.septicum; 'c' i.e., C. histolyticum", 'role': 'assistant'}]