This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oral Cavity, Subject name: Surgery
[{'content': 'The most frequent tooth to be impacted is: \nSelect and explain. \nA. Lower third molar, B. Lower canine, C. Upper third molar, D. Upper premolar', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Lower third molar* Impacted tooth: MC in Lower 3rd Molar > upper 3rd Molar> Upper canine* Impacted tooth can produce referred pain via the direct impingement of Auriculotemporal nerve.', 'role': 'assistant'}]