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': 'Calculocementum \nSelect and explain. \nA. Non-calcified structures, B. Calculus embedded deeply in cementum, C. Non-attachment mechanisms, D. Non similar to cementum', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]