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': 'Antrochoanal polyp opens In which meant \nSelect and explain. \nA. Middle meatus, B. Superior meatus, C. Inferior meatus, D. Sphenoethmoidal recess', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ANTROCHOANAL POLYP most commonly seen in children.\n\nThey are unilateral, usually arises from the mucosa of maxillary antrum near its accessory ostium comes out of it & grows in the channel & nasal cavity.\n\nMaxillary sinus opens into the middle meatus.', 'role': 'assistant'}]