The correct answer is OC (sound through a door)
How do I know this?
There are four things a wave can do.
1) reflection - this is when a wave hits something and bounces back perfectly.
2) absorption - this is when a wave gets absorbed (it does not come out the other side).
3) transmission - this is what your question is talking about. This is when a wave passes through something and comes out the other side unchanged
4) refraction- this is when a wave passes through something and gets bent
When we hear an echo, this is because a sound wave has been reflected.
When a fish looks larger than it really is, this is because the light wave that allows us to see this fish is bending
When you see yourself in the mirror, this is because light waves are reflected.
Sound is heard through a door, because the sound wave is *transmitted* through the door and comes out the other side. That’s why we can hear it.
Hope that makes sense
