If your throttle is stuck and twisting it back and forth does not free it, what should you do?

Answer: B — Operate the engine cut-off switch

In the scenario where your throttle is stuck and attempting to twist it back and forth fails to resolve the issue, the appropriate action is to operate the engine cut-off switch. This switch is specifically designed to quickly shut off the engine in emergencies, which is crucial in preventing loss of control over the motorcycle. Engaging the cut-off switch ensures that the engine ceases to provide power to the wheels, allowing you to regain control of the motorcycle and safely bring it to a stop. Operating the cut-off switch effectively eliminates the risk of accelerating uncontrollably, which could create a dangerous situation. Additionally, shifting into neutral could be considered; however, if the throttle is stuck, a neutral shift might not be immediately practical or safe, depending on the circumstances. Relying on rear brakes alone may also not provide the needed stopping power, especially if the motorcycle is still accelerating due to the stuck throttle. Thus, using the engine cut-off switch is the safest and most effective response in this situation.