The pitch of sound refers to how high or low a sound is perceived by the human ear. It is determined by the frequency of the vibrating body producing the sound. Here is a detailed explanation of why the correct answer is option 'C' (frequency):

1. **Definition of pitch**: Pitch is a subjective perception of the frequency of a sound wave. It is the quality that allows us to distinguish between sounds that have the same loudness and duration but differ in their frequency content. A high-pitched sound is perceived as a high-frequency sound, while a low-pitched sound is perceived as a low-frequency sound.

2. **Frequency of a vibrating body**: The frequency of a vibrating body refers to the number of complete vibrations or cycles it completes in one second. It is measured in hertz (Hz). The higher the frequency, the higher the pitch of the sound produced.

3. **Relation between frequency and pitch**: The human ear is sensitive to a range of frequencies, typically from 20 Hz to 20,000 Hz. When an object vibrates at a higher frequency, it produces a sound wave with a higher pitch. Conversely, when an object vibrates at a lower frequency, it produces a sound wave with a lower pitch.

4. **Amplitude and pitch**: Amplitude refers to the maximum displacement of particles in a medium caused by a sound wave. It determines the loudness or volume of a sound. However, it does not directly affect the pitch of the sound. Two sound waves with the same frequency but different amplitudes will have the same pitch but different loudness.

5. **Noise and pitch**: Noise refers to an unpleasant or unwanted sound that lacks a specific pitch. It is characterized by its random and irregular vibrations. Unlike pitched sounds, noise does not have a discernible frequency or musical tone. Therefore, noise does not determine the pitch of a sound.

6. **Medium of propagation and pitch**: The medium through which sound travels can affect its speed and intensity but does not directly influence its pitch. The pitch of a sound remains the same regardless of the medium through which it propagates, as long as the frequency of the vibrating body remains constant.

In conclusion, the pitch of sound is determined by the frequency of the vibrating body producing the sound. The higher the frequency, the higher the pitch, and vice versa. Amplitude, noise, and the medium of propagation do not directly affect the pitch of sound.

Because sound waves traveling through air are longitudinal waves that produce high- and low-pressure disturbances of the particles of the air at a given frequency, the ear has an ability to detect such frequencies and associate them with the pitch of the sound...if u need more just let me know..will try to good..