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: Social & Preventive Medicine
Acceptable noise level in industries ? 
Select and explain. 
A. 25-30 dB, B. 30-40 dB, C. 40-50 dB, D. 60-80 dB
C: 40-50 dB
Answer: C: 40-50 dB 
Explanation: Ans. is 'c' i.e.,40 50 dB