Explanation:

The Central Pollution Control Board (CPCB) in India specifies noise pollution standards. For Silent Zones (areas around hospitals, educational institutions, courts, religious places), the permissible noise limit during the day (6 AM to 10 PM) is $50 \text{ dB}$. This is a standard regulatory value. Option (2) $60 \text{ dB}$ is typically for Commercial Areas during the day. Option (3) $70 \text{ dB}$ is generally for Industrial Areas during the day. Option (4) $80 \text{ dB}$ is significantly higher than permissible limits for any designated zone during the day, indicating severe noise pollution.