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 incisal edges and the incisal thirds of facial surfaces of mandibular incisors and canines generally oppose lingual surfaces of maxillary incisor and canines: \nSelect and explain. \nA. Within the incisal thirds, B. At the junction of middle and cervical thirds, C. At the linguo cervical ridges, D. Immediately incisal to cingulam', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]