Answer: Thermometer should register 32°F when using the ice point method of calibration.
Explanation: Thermometers used in the kitchen should be calibrated on regular basis, therefore option 1 is incorrect. If thermometers are sent to the company, then the people would need more thermometers in spare, which is not economical. Also, the method of calibration is easy and can be conducted anywhere. Thus, option 4 is also incorrect. Boiling water is also used for calibration, but it is more time consuming and handling hot water can be dangerous. So, best method is ice point method.
