If a humidifier motor operates properly, which of the following scenarios must be true?

The scenario that states "all systems are functioning as designed" is the most comprehensive and accurate interpretation of what it means for a humidifier motor to operate properly. For the humidifier motor to function correctly, several interconnected systems must work together seamlessly.

When all systems are functioning as designed, it indicates that the motor, wiring, air supply, and water supply are all in their optimal condition. Each of these components plays a critical role in the overall operation of the humidifier. If one part fails or is not performing correctly, it can negatively impact the motor's operation or cause it to falter.

For example, if the humidifier motor is wired incorrectly or the air supply is obstructed, it could impair the motor's function, even if the water supply is sufficient. This makes it clear that it's not enough for just one component to work; the entire system needs to be operational to ensure the motor runs properly. Thus, stating that all systems are functioning as designed encompasses all the necessary conditions for optimal motor performance.