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: Pathology
Which of the following is a non-destructive method of age estimation in adults? 
Select and explain. 
A. Assessment of root dentin translucency, B. Amino acid racemisation, C. Evaluation of tooth cementum annulations, D. Pulp to tooth ratio of canines
D: Pulp to tooth ratio of canines
Answer: D: Pulp to tooth ratio of canines 
Explanation: None