Describe what happens to water waves when they strike a flat surface?

In this case reflection occurs.

Explanation:

This happens when they bounce on objects that they can not pass through.

Hope it helps

okay.

a.) is the correct answer.

explanation:

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me