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 following is true about Mantle dentin 
Select and explain. 
A. 1st formed dentin just beneath DEJ, B. Calcified by matrix vesicles, C. Both, D. None
C: Both
Answer: C: Both 
Explanation: None