D. The graph shows that the shape was reflected horizontally along some line. To figure out that line, we need to find out the midpoint of two points from the shapes. Let’s use point Z and point Z’. Since it is being reflected horizontally we need to find the y coordinates. The y coordinate of Z is 1 and the y coordinate of Z’ is -1. The midpoint of those is 0. That means the line of reflection is across the z axis.