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
Indication of BAHA (Bone-anclored hearing aid) 
Select and explain. 
A. Bilateral hearing loss, B. Sensorineural hearing loss, C. Congenital canal atresia, D. All of the above
C: Congenital canal atresia
Answer: C: Congenital canal atresia 
Explanation: Ans. is 'c' i.e., Congenital canal atresia Indications for BAHA When air-conduction (AC) hearing aid connot be used; Canal atresia, congenital or acquired, not amenable to treatment. Chronic ear discharge, not amenable to treatment. Excessive feedback and discomfo from air-conduction hearing aid. Conductive or mixed hearing loss, e.g. otoscierosis and tympanosclerosis where surgery is contraindicated. Single-sided hearing loss.