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
Fluctuating recurring variable sensorineural deafness is seen in - 
Select and explain. 
A. Serous otitis media, B. Heamotympanum, C. Perilabyrinthine fistula, D. Labrinthine concussion
C: Perilabyrinthine fistula
Answer: C: Perilabyrinthine fistula 
Explanation: None