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': 'Scaling and root planning is performed \nSelect and explain. \nA. As initial treatment, B. Post surgically, C. In only gingival enlargements, D. after only antibiotics', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]