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': 'Radiopaque irregularity associated with the roots of mandibular central incisors most likely represent? \nSelect and explain. \nA. Root Caries, B. Subgingival Calculus, C. Subgingival Pellicle, D. Hyperplastic Cementum', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]