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
Which of the areas of the tooth is most sensitive during cavity preparation? 
Select and explain. 
A. Enamel (anterior teeth), B. Enamel (Posterior teeth), C. Dentin, D. Dentinoenamel junction
D: Dentinoenamel junction
Answer: D: Dentinoenamel junction 
Explanation: None