determine which of the following must change when pitch gets higher a. amplitude b. frequency c. wavelength d. intensity e. speed of sound waves

Higher pitch means higher frequency.

But higher frequency also means shorter wavelength, because the product of (frequency) x (wavelength) is the wave-speed, so it doesn't change.

So (b) and (c) must both change.

Th Correct Answer is C

Explanation:

Changing Pitch

The four characteristics of the series that influence its frequency are density, diameter, tension, and length. These characteristics are illustrated below: While the length of a sequence is modified, it will reverberate with a distinct wavelength. Lower strings have a greater frequency and therefore more powerful pitch.