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
Glycerol test is done in - 
Select and explain. 
A. Otosclerosis, B. Lateral sinus thrombosis, C. Meniere's disease, D. None of the above
C: Meniere's disease
Answer: C: Meniere's disease 
Explanation: Glycerol is a dehydrating agent. When given orally, it reduces endolymph pressure and causes improvement in hearing as evidenced by an improvement of 10 dB or 10% gain in discrimination score in Meniere’s disease patients.