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': 'Calculus attaches to tooth structure by the following\nways except: \nSelect and explain. \nA. By means of an organic pellicle, B. Mechanical locking in surface irregularities, C. Close adaptation to undersurface depressions, D. Tags of calcium phosphate reacting chemically with enamel walls', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]