Answer: C. The amount earned is a function of the number of hours worked.
Step-by-step explanation:
Since, a function is always the type of y= f(x), where x is independent variable and y is dependent variable which is dependent on the value of x.
Here, a graph of Olivia's earning per hour is given.
Since, it is the obvious thing that the earning will depend on hours she works.
Thus, we can say that earning is dependent variable while hours is independent variable.
Therefore, earning makes the y-axis and number of hours makes the x-axis.
So, option C is correct.