Final answer:
A grill thermometer should be used to periodically check that the grill temperature is correct for food safety. Additionally, understanding Gay-Lussac's Law is useful for determining when to refill a propane tank, as pressure readings can vary with temperature.
Step-by-step explanation:
A grill thermometer should be used to ensure that food reaches a high enough temperature to kill any bacteria it may contain. The best practice is to keep the thermometer on the line and periodically check the temperature of each grill to make sure it is correct, as stated in option A. This helps in maintaining the safety and quality of the food being prepared.
Understanding the temperature of your grill is crucial, as is monitoring the amount of propane in your tank. Pressure gauges can help determine how much propane is left, but remember that the reading can vary with the ambient air temperature due to Gay-Lussac's Law. Therefore, it's important to consider the air temperature when deciding whether you need to refill your propane tank.