To interpret the graph and determine the rate of change, we need to understand how Jasper's rental fee is structured. The flat fee of $25 is a constant charge that he pays regardless of the time he uses the truck. The hourly charge of $15 means that for every hour he rents the truck, the total cost increases by $15.
The rate of change is based on the variable part of the cost, which is the hourly charge. Since he is charged $15 for every hour of usage, the rate of change is:
15
Thus, the correct response from the options given would be:
15