Consider the following.
graphs are made of coordinates, Coordinates are made of x and y values
x values are typically the input while y values are the output
Basically
The x values are the time (input) and the y values are the cost (output)
Thus
The answer would be graph D
Becuase
For the first set of records
It would be up to 60 minutes (which is either 1 hr or less than one hr) for 5$
Less than or equal to 1 is 5$
So yeah D