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': 'Frontal sinus drain into - \nSelect and explain. \nA. Superior meatus, B. Inf. meatus, C. Middle meatus, D. Ethmoid recess', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]