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': 'Muscle which has influence in the formation of buccal frenum of maxilla: \nSelect and explain. \nA. Levator anguli oris, B. Quadratus labii superioris, C. Triangularis, D. Inferioris', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Buccal frenum of maxilla contains\xa0levator anguli oris (caninus), buccinator and orbicularis oris.\nBuccal frenum of mandible contains triangularis or depressor anguli oris.', 'role': 'assistant'}]