what is the name of the perceived change in a sound waves frequency due to motion between the observer and…

Brief Explanations:

The Doppler effect is the perceived change in a wave's frequency (including sound waves) due to relative motion between the source and the observer. Diffraction is the bending of waves around obstacles, reflection is the bouncing of waves off a surface, and resonance is the phenomenon where a system vibrates at maximum amplitude at a specific frequency.

Answer:

B. Doppler effect