Answer:
d)

Step-by-step explanation:
β₁ = sound level of sound at rock concert = 120 dB
β₂ = sound level of sound due to whisper = 21 dB
I₁ = Intensity of sound at rock concert
I₂ = Intensity of sound due to whisper
sound level of sound at rock concert is given as


Eq-1
sound level due to whisper is given as


Eq-2
subtracting Eq-2 from Eq-1


