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': 'Chemical plaque control \nSelect and explain. \nA. is an effective replacement for mechanical plaque control, B. is especially recommended after periodontal surgery, C. is best achieved using cetylpyridium chloride mouth washes, D. is of no use', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]