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': "Sharpey's fibres are present in: \nSelect and explain. \nA. Bone, B. Periosteum, C. Periodontal ligament, D. All of the above", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]