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
[{'content': 'Which of the following is true about cementum \nSelect and explain. \nA. It forms a part of periodontium and is avascular., B. Its function is to attach tooth to PDL., C. It provides anchorage to the tooth., D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]