This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
[{'content': 'All Clostridia cause myonecrosis except- \nSelect and explain. \nA. C septicum, B. C difficle, C. Cnovyi, D. C welchii', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., C difficle o Anaerobic myonecrosis (gas gangrene) is caused by-Cl perfringens (Cl welchii) - most common (80%)Cl SepticumCl novyiCl histolyticumo Cl difficle causes Clostridium difficle-associated disease (CDAD) which also includes pseudomembranous enterocolitis.", 'role': 'assistant'}]