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 fibers are completely calcified found in cementum: \nSelect and explain. \nA. Extrinsic fibres., B. Intrinsic fibers., C. Sharpey's fibers., D. All of the above.", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]