A plumber charges a one-time site visit fee to evaluate a potential job. If he accepts the job, he charges an hourly rate plus the cost of any materials needed to complete the job. He also charges for tax, only on the cost of the materials. If the cost of completing a job that takes $'x'$ hours is given by the function $c(x) = 50x + 1.25 (83.5) + 75$, then the term $1.25(83.5 )$ represents

Question

$\begin{array}{1 1} (a)\; \text{The hourly rate} \\(b)\;\text{The site visit fee} \\ (c)\; \text{The cost of materials including tax}\\ (d)\; \text{The cost of materials not including tax} \end{array}$