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
Acoustic dip occurs at - 
Select and explain. 
A. 2000Hz, B. 4000 Hz, C. 500Hz, D. 1500 Hz
B: 4000 Hz
Answer: B: 4000 Hz 
Explanation: Acoustic dip is dip seen in pure tone audiometry due to noise trauma, which is seen typically at 4 kHz i.e. 4000 Hz.