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
Acellular cementum 
Select and explain. 
A. Has no cells, B. Has cells trapped in cementum called cementocytes, C. Is formed throughout life, D. All of the above
A: Has no cells
Answer: A: Has no cells 
Explanation: None