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': 'Necrotizing fasciitis is caused by, all except \nSelect and explain. \nA. Staphylococcus aureus, B. Beta haemolytic streptococci, C. Clostridium perfringens, D. Pneumococcus', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. is. d. Pneumococcus', 'role': 'assistant'}]