If we strike a table lightly, we hear a soft sound but if we hit the table hard, a loud sound is heard because:

A phenomenon known as vibration is when an object oscillates about its equilibrium position. The vibration may be regular, like that of a pendulum swinging, or it may be erratic.
When an object vibrates, it causes the medium it is in to vibrate, creating a sound wave.
The greatest distance an object can travel on either side of its equilibrium position can be used to measure the amplitude of a vibration.

The number of vibrations that take place per second determines a vibration's frequency. It can be explained as the motion of a vibrating item. When an object goes from one extreme position to the other and then back to the initial extreme position, a complete vibration happens.The vibration's frequency is defined as the number of full cycles that take place in a second. Frequency is measured in Hz (hertz). One whole cycle per second is equivalent to one hertz.
Distance units are used to quantify amplitude. The vibration's amplitude determines how loud the sound will be.
Lightly striking the table causes a smooth vibration with a little amplitude, which produces a quiet sound.
When we strike the table firmly, more amplitude is produced in the vibration, which results in a louder sound.

Thus. options C  is correct.