What might be a problem if you receive a report that your audio signal through an FM repeater is distorted or unintelligible?

Distortion on an FM repeater can stem from operator error, equipment misalignment, or environmental factors. If you speak too loudly or too closely to the microphone, you will cause over-deviation, leading to harsh, clipped audio. If your transmitter is slightly off-frequency, the repeater's receiver cannot demodulate your signal cleanly. Furthermore, environmental factors play a major role. Operating from a bad location can cause multi-path interference (often called 'picket-fencing' when moving) or result in a weak signal full of static. Since all of these issues will result in unintelligible or distorted audio, all the choices are correct.