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
Rinne's test is negative if minimum deafness is - 
Select and explain. 
A. 15-20 dB, B. 25-30 dB, C. 35-40 dB, D. 15-50 dB
A: 15-20 dB
Answer: A: 15-20 dB 
Explanation: As discussed in the text in Rinnies test—air conduction of the ear is compared with its bone conduction.
Hence there is false negative Rinne test (BC > AC).