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: Dental
[{'content': 'Bacteria most commonly isolated from root canals is \nSelect and explain. \nA. Actinomyces, B. Streptococci, C. Staphylococci, D. Fusobacterium', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]