This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2018, Subject name: ENT
[{'content': "Dip at 4000hz in pure Tone audiometry indicates:- \nSelect and explain. \nA. Otosclerosis, B. Meniere's disease, C. Noise induced hearing loss, D. Age related hearing loss", 'role': 'user'}, {'content': "Answer: C \nExplanation: 2000Hz / Carha's Notch: seen in otosclerosis (CHL)4000Hz Dip/boiler's notch :seen in noise induced hearing loss (SNHL)Both are seen in bone conduction.", 'role': 'assistant'}]