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: ENT
[{'content': 'Stensons duct of parotid opens opposite to \nSelect and explain. \nA. Upper second premolar, B. Lower second premolar, C. Lower second molar, D. Upper second molar', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]