The correct answer is option 2: frequency.

Pitch is a characteristic of sound that refers to how high or low a sound is perceived. This perception of pitch is determined by the frequency of the sound wave. Frequency is the number of cycles or vibrations that occur in one second, and it is measured in hertz (Hz).

Higher frequency sound waves have a higher pitch and are perceived as being higher in frequency, while lower frequency sound waves have a lower pitch and are perceived as being lower in frequency. For example, a high-pitched sound like a bird chirping has a higher frequency, while a low-pitched sound like a deep voice has a lower frequency.

Intensity, on the other hand, refers to the loudness or softness of a sound. It is determined by the amplitude or strength of the sound wave. Quality refers to the unique characteristics of a sound that distinguishes it from other sounds, such as the timbre or tone color.

Therefore, the correct answer is option 2: frequency, as pitch is directly dependent on the frequency of a sound.