What can cause a motorcycle to oscillate at high speed?

Your answer is correct because all three factors can cause a motorcycle to oscillate at high speed.

1. Unbalanced wheels create uneven rotation, leading to vibrations that can cause oscillations.
2. Uneven road surfaces can disturb the stability of the motorcycle, especially at high speeds, triggering oscillations.
3. Heavy luggage at the rear shifts the center of gravity backward, which can reduce front wheel traction and make the bike prone to wobbling or oscillations.

Understanding these helps in maintaining stability by ensuring wheels are balanced, riding cautiously on rough roads, and distributing load properly on the motorcycle.