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
Which of the following causes maximum hearing loss? 
Select and explain. 
A. Complete obstruction of ear canal, B. Perforation of tympanic membrane, C. Ossicular interruption with intact tympanic membrane, D. Ossicular interruption with perforation
C: Ossicular interruption with intact tympanic membrane
Answer: C: Ossicular interruption with intact tympanic membrane 
Explanation: Average hearing loss in different lesions: Complete obstruction of ear canal = 30db Perforation of tympanic membrane = 10-40 db Ossicular interruption with intact tympanic membrane= 54db Ossicular interruption with perforation = 38db Closure of oval window can cause 60 db hearing loss