15. Which is quieter, a room with hanging curtains or one with bare concrete walls?
Why?
A. Both rooms have the tendency to be peaceful and to be quiet depending
on the location.
B. It is quieter in a room with concrete walls because sound travels faster in
medium with the higher elastic property at the molecular level.
C. It is quieter in a room with curtains because the bare concrete wall brings
about multiple reflections of sound.
D. It is quieter in a room with bare walls because hanging curtains enhance
the effect of sound reverberation.​