Question

4. Which of the following scenarios would cause a sound to stop being produced?A. A molecule moves in the same direction as a wave.B. The vibration of the point in the medium endc A molecule moves through its normal position to the opposite side of its normal positionD. The vibration results in a molecule moving vertically.

Answer 1

' B ' .
"Sound" is all vibrations in the medium.  Whether it happens to be water,
air, steel, whatever is vibrating, the sound is the result of the vibrations. 
When the vibrating stops, the sound stops.

Answer 2

Answer;

B. The vibration of the point in the medium end

The vibration of the point in the medium ends would cause a sound to stop being produced.

Explanation;

-Sound is produced when something vibrates. The vibrating body causes the medium (water, air, etc.) around it to vibrate.

-Vibrations in air are called traveling longitudinal waves, which we can hear. Sound waves consist of areas of high and low pressure called compressions and rarefactions, respectively.

-Therefore, without vibration of particles, sound would not be produced and hence, if he vibration of the point in the medium end then it would cause a sound to stop being produced.