The points on this graph represent a relationship between x- and y-values. Which statement about the relationship is true?

Graph with coordinates (0, 0). Line extending from (0, 0) has points plotted at approximately (2, 1.5); (4, 3); (6, 4.5).

It cannot be proportional because when x increases by 2 units, y only increases by 1.5 units.

It cannot be proportional because you do not know the actual x- and y-values.

It must be proportional because the points in the graph fall in a straight line.

It must be proportional because the graph is a straight line passing through the origin.

It must be proportional because the graph is a straight line passing through the origin.

The statement "It must be proportional because the graph is a straight line passing through the origin" is true.