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': 'A pure tone audiogram with a dip at 2000 Hz is characteristic of- \nSelect and explain. \nA. Presbyacusis, B. Ototoxicity, C. Otosclerosis, D. Noise induced hearing loss', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Dip at 2000 Hz in PTA called as carharts notch is characteristic of otosclerosis.', 'role': 'assistant'}]