Which of the following represents the decibel level of rustling of tree leaves in normal circumstance?

উত্তর দেখান ও ব্যাখ্যা

উত্তর: (B) 20 dB

ব্যাখ্যা

Rustling leaves are about 20 dB (a whisper is about 30 dB, normal conversation about 60 dB).