I believe the answer is D) The relationship is not proportional because the unit rates are not the same.
I think this because the unit rate is not the same for every point. The unit rate looks like it is supposed to be $10 for every hour. But, the graph skips the 3 hours and goes to 4. So, the graph says that 4 hours would be $30 when 3 hours is supposed to be $30 and 4 hours is supposed to be $40.
Also, if you draw a line on the graph, it would probably only go through 2 of the points.
I could be wrong but if I am, I am so sorry.