This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
[{'content': "Carhart's notch is seen in \nSelect and explain. \nA. Otosclerosis, B. Acoustic neuroma, C. Meneir's disease, D. CSOM", 'role': 'user'}, {'content': "Answer: A \nExplanation: i.e. (Otosclerosis): (99-Dhingra 5th)* Carhart's notch - maximum at 2000 Hz or 2KHZ carharts notch disappears after successful stapedectomy in OTOSCLEROSIS* Schwartze sign - flamingo-pink bluish tympanic membrane due to hyperaemia of the promontory and affords good evidence that the otosclerotic process is an active phase in OTOSCLEROSISOTOSCLEROSIS (otospongiosis)- Commonest site -fissula ante fenestram**- Painless and progressive bilateral conductive deafness**- Paracusis willisii (hears better in noisy than quite surroundings)**- Tinnitus, vertigo, monotonous speech**", 'role': 'assistant'}]