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': "Teunissen's classification is used in classification of congenital anomalies of: \nSelect and explain. \nA. Middle ear, B. Larynx, C. Trachea, D. Pharynx", 'role': 'user'}, {'content': "Answer: A \nExplanation: Historically, congenital malformations of the ear have been divided into major and minor types with the latter limited to the middle ear alone. Teunissen's classification system is based on the site of involvement and aids in determining the appropriateness for surgery.", 'role': 'assistant'}]