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
Calculus attaches to tooth structure by the following
ways except: 
Select and explain. 
A. 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
D: Tags of calcium phosphate reacting chemically with enamel walls
Answer: D: Tags of calcium phosphate reacting chemically with enamel walls 
Explanation: None