We can find the unit price at the print shop by taking one point of the line and dividing its y-coordinate (price) by its x-coordinate (the number of pages printed).
For example, we can see that the line goes through the point (2,1), then we can take that point to calculate the price per page as mentioned, like this:
unit price = Total price/number of pages = 1$/2 = 0.5$
Then, the answer is 0.5$ per page (option D)
