Answer: the correct option is (C) 100 + 50h.
Step-by-step explanation: Given that a plumber charges a flat rate of $100 and $50 per hour, h, for a job.
We are to select the expression that represents the total cost for the job.
According to the given information, we have
the charge of the plumber in h hours is given by

Since there is a flat rate of $100, so the total cost for the job will be

Thus, the required total cost for the job is

Option (C) is CORRECT.