The "coefficient of absorption" of a soundproofing material is
the fraction of sound energy that goes into the material, gets
absorbed, doesn't come out, and is never heard again.
So, sample C would be the best choice, because the percentage
of the energy in an incident wave that gets absorbed in this material
is the greatest, and the percentage of the energy that remains in a
reflected wave from this material is the smallest. (Choice-B)