The option is a cost function of time.
We have given that,
At a car repair shop, the cost of a repair depends on the time the mechanic works.
We have to determine the, The following shows this idea expressed in function notation.
In production, research, retail, and accounting, a cost is the value of money that has been used up to produce something or deliver a service and hence is not available for use anymore.
Therefore, the option is a cost function of time.
Therefore option D is correct.
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