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': '"Sulfur granules" are a feature of: \nSelect and explain. \nA. Clostridia, B. Actinomyces, C. Aspergillus, D. Nocardia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Actinomyce', 'role': 'assistant'}]