Final answer:
Base pay is the option that is not a pay differential. Pay differentials like hazard pay, shift pay, and overtime are additional compensations on top of base pay for various working conditions.
Step-by-step explanation:
The student has asked which option is not a pay differential. Pay differentials refer to the various forms of additional compensation provided for working under certain conditions or for specific job roles that are beyond regular duties. The options provided include A. Hazard pay, which compensates employees for performing tasks that involve physical danger; B. Shift pay, which is extra pay for employees working shifts that are outside the normal working hours; C. Base pay, which is the initial rate of compensation an employee receives excluding any extra pay for overtime or working under different conditions; and D. Overtime, which is the additional pay given for hours worked above the standard for the job.
In this list, the option that is not a pay differential is C. Base pay. Base pay is the standard rate of compensation before any differentials are applied. As opposed to hazard pay, shift pay, and overtime which are all forms of differential pay, base pay is considered the standard rate without regard to any specific conditions or hours worked.