You are given a mathematical question described with an open-ended vocabulary. Questions in this task involve real-world situations, describing a mathematical problem. You are also given 4 or 5 answer options (associated with "A", "B", "C", "D", "E"). Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D', 'E'. LaTeX mathematical format (the standard way to express mathematical expressions in the typesetting software known as LaTeX) is used to express equations. Each question is solvable with high school math knowledge. Give only one answer for each question.

At a certain grocery store, \(a\) customers each spend an average of \$30 every \(b\) hours. In dollars, how much do customers spend at this store in \(c\) hours?
(A)\(\frac { 30c } { ab } \) (B)\(\frac { bc } { 30a } \) (C)\(\frac { 30bc } { a } \) (D)\(\frac { 30ac } { b } \) (E)\(\frac { 30b } { ac } \)
D
The average spending per customer is \$30 every \(b\) hours. Since there are \(a\) customers, the total spending over a period of \(c\) hours would be the average spending from each customer times the number of customers times the number of hours, i.e., \$30ac/b. Therefore, the answer is (D)..