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
Flat & dome shaped graph in tympanogram is found in - 
Select and explain. 
A. Oto sclerosis, B. Ossicular discontinuity, C. TM perforation, D. Middle ear fluid
D: Middle ear fluid
Answer: D: Middle ear fluid 
Explanation: None