Question

Your boss asks you to design a room that can be as soundproof as possible and provides you with three samples of material. The only information on each sample's label is the material's coefficient of absorption. The coefficient of absorption listed on Sample A is 30%, on Sample B is 47%, and on Sample C is 62%. When your boss asks for your choice and the reasoning behind it, what would you tell him?
A. Sample C would be best, because the percentage of the energy in an incident wave that remains in a reflected wave from this material is the largest.
B. Sample A would be best, because the percentage of the energy in an incident wave that remains in a reflected wave from this material is the largest.
C. Sample C would be best, because the percentage of the energy in an incident wave that remains in a reflected wave from this material is the smallest.
D. Sample A would be best, because the percentage of the energy in an incident wave that remains in a reflected wave from this material is the smallest.

Answer 1

C. Sample C would be best, because the percentage of the energy
in an incident wave that remains in a reflected wave from this material
is the smallest.

The coefficient of absorption is the percentage of incident sound
that's absorbed.  So the highest coefficient of absorption results in
the smallest percentage of the energy in an incident wave that remains.
That's what you want.