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': 'Microbrasion is a procedure in clinical orthodontics\nperformed to \nSelect and explain. \nA. Clean the bracket base, B. Clean the archwire, C. Polishing the bracket, D. Removal of white spot lesions', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]