Answer:
D. people per hour because the dependent quantity is the people
Explanation:
The variable that we can be change is called the Independent variable.
The dependent variable depends upon the independent variable, as we change the value of the independent variable the value of the dependent variable is also get changed.
Here people is the dependent variable and hours is independent variable as time passes the number of visitors of the park will be change.
And, Number of people can be calculate according to the hours. So, the word use here should be "hours per person".
Thus, Option (D) is the correct option only.