The pitch of a sound wave depends upon which one of its following characteristics?

The pitch of a sound wave is primarily determined by its frequency. Pitch is the subjective perception of how shrill or deep a sound is; a high-frequency sound wave corresponds to a high pitch, while a low-frequency wave corresponds to a low pitch. Frequency is defined as the number of waves passing a specific point per second, measured in Hertz (Hz) [2]. While pitch depends on frequency, other characteristics like loudness are determined by the amplitude of the sound wave. The speed of sound is generally constant in a uniform medium and depends on the state of the medium (such as density and temperature) rather than the frequency or pitch of the sound itself [1]. Therefore, the brain associates musical pitch specifically with the frequency of the pressure fluctuations detected by the ear [1].

Sources

1. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 15: Tsunami > Basics > p. 192
2. [1] https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/doppler.html