The definite integral from one to five of R of T DT. This is the area under this rate curve. R of T is the rate at which Julia makes revenue on a monthly basis. So if you take the area under that rate curve, that's going to give you the net change in revenue from month one to month five, how much that increased. So if you add that to the amount that she made in month one, well that tells you the total she makes from essentially time zero all the way to month five. And they're saying that is equal to 19. So let's see which of these choices are consistent with that.