The points on this graph represent a relationship between x- and y-values. Which statement about the relationship is true?
Line graph. Coordinates of (0, 0) are marked on graph. Other points marked in a straight line on the graph are as follows: (1, 2.5); (3, 3.5); (5, 4.5).
It cannot be proportional because the straight line through the points does not go through the origin.
It cannot be proportional because the y-values are not whole numbers.
It must be proportional because the points lie in a straight line.
It must be proportional because each time x increases by 2, y increases by 1.