The steepness of a graph is given by its gradient; in this case both y = 12x + 7 and y = 12x + 2 have a gradient of 12 so this doesn't change and thus A and D are incorrect. Now if we take the form of the graph y = mx + c, c is the y-intercept. The original graph had a y-intercept of 7 and the new one has a y-intercept of 2, so we can conclude that the graph would have been shifted down - thus C is the correct answer.
