Answer:
2
Explanation:
The first graph does not represent the linear relationship, because the slope of the line connecting points (3,60) and (4,90) is

and the slope of the line connecting points (4,90) and (5,110) is

Since slopes 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 llinear relationship.