What is the ruling if a warmup device (donut) flies off a bat during a game?

The correct ruling in this scenario is that the warmup device, also known as a "donut," is illegal if it has shown signs of wear or damage. In official rules, any equipment that is used in the game must comply with specific standards concerning its condition and integrity. If the donut detaches from the bat during play, it suggests that it may not be in compliance with these standards, leading to the conclusion that it could be considered illegal for that reason.

This ruling ensures that all equipment used in the game maintains safety and performance standards, as any defective or damaged device could potentially lead to unfair advantages or safety hazards. Therefore, if the donut is found to be worn or damaged when it flies off, it cannot be used legally in the game, which justifies the ruling of it being illegal.

The other options are not consistent with the rules governing game equipment and do not reflect the standards expected in competitive play. For instance, a new donut being legal does not automatically apply if it demonstrated wear during use, and penalizing the batter or continuing without penalties fails to address the need for equipment compliance.