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': 'The most easily perforated tooth with a slight mesial or distal angulation of bur after a mandibular central incisor is: \nSelect and explain. \nA. Maxillary premolar, B. Maxillary molar, C. Mandibular premolar, D. Maxillary canine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]