This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nose and PNS, Subject name: ENT
[{'content': 'Antrochoanal polyp opens In which meatus: \nSelect and explain. \nA. Middle meatus, B. Superior meatus, C. Inferior meatus, D. Sphenoethmoidal recess', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans: A Middle Meatus Ref: Dhingra's ENT 6th ed./ 173-75* ANTROCHOANAL POLYP most commonly seen in children. They are unilateral, usually arises from the mucosa of maxillary antrum near its accessory ostium comes out of it & grows in the chonna & nasal cavity.* Maxillary sinus opens into the middle meatus.", 'role': 'assistant'}]