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': "Remnants of the Hertwig's root sheath are found in \nSelect and explain. \nA. Gingiva, B. Alveolar bone, C. Periodontal ligament, D. Cementum", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]