Which of the Following Statements Regarding Calibration of Thermometers Is

Which of the following statements regarding calibration of thermometers is correct?

A) Thermometers can be calibrated by an ice-water method using a 50% ice/50% water mixture at least 2 inches deep.
B) Thermometers can be calibrated by a boiling-water method at 212 degrees F.
C) Thermometers should be calibrated before the work shift begins.
D) If a thermometer is dropped on the floor, it should be re-calibrated.
E) all of the above answers are correct