This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and Health, Subject name: Social & Preventive Medicine
The 'acceptable' noise level is: 
Select and explain. 
A. 85 dB, B. 90 dB, C. 95 dB, D. 100 dB
A: 85 dB
Answer: A: 85 dB 
Explanation: (85 dB): Ref: (648-Park 20th)* "A daily exposure up to 85 dB is about the limit people can tolerate without substantial damage to their hearing"* Auditory fatigue - appears in the 90 dB region and greatest at 4000 Hz* Deafness - Most temporary hearing loss occurs in frequency range between 4,000 to 6,000 Hz* Repeated or continuous exposure to noise around 100 decibels may result in permanent hearing loss* Exposure to noise above 160dB may rupture the tympanic membrane and cause permanent loss of hearing* Most disturbances to speech communication lies in the 300 - 500 Hz range.