Basically think of the original image increasing in size, so it cant change in anyway, as in the angles are are proportional. So just look at the original image, and look for the one that looks exactly the same, just the size increased.
Since a slope differe, this is not linear relationship. Simply, if you connect all points on the graph, they will not lie on the same line. Two next graphs represent the linear relationships, so they represent the linear relationship.
