sound waves are produced when something is caused to reflect. vibrate. slow down. get warmer.

Brief Explanations:

Sound waves are generated by vibrations. When an object vibrates, it causes the surrounding medium (such as air) to vibrate, creating sound waves. Reflection is related to how sound waves bounce off surfaces, slowing - down is not the cause of sound - wave production, and getting warmer is also not the cause of sound - wave generation.

Answer:

B. vibrate