A 26 year old woman has become aware of increasing right sided hearing deficiency since her recent pregnancy. Her eardrums are normal. Her hearing tests show: BC-normal. Weber test lateralizes to the right ear. What is the single most likely diagnosis?

The key is D. Otosclerosis. [There are no features of encephalopathy. As Weber test is lateralized it is unlikely to be functional hearing loss. In tympanosclerosis ear drum becomes chalky white. So as the ear drum is normal it is not tympanosclerosis. Weber test is lateralized to right and deafness is also on the right. So it not sensorineural deafness but conductive deafness which makes otosclerosis as the most likely diagnosis].