A Useful Way to Measure the Productivity of a Workforce

A useful way to measure the productivity of a workforce is:

A) to determine the total cost of people required for each unit of output.
B) to determine the total cost of people required for an output of 100 units.
C) to determine the total cost of people required to complete a day's worth of work.
D) to determine the total cost of people required to complete a year's worth of work.