The given graph is a straight line which is passing through the origin.Any line has a constant rate of increase or decrease.The constant of the equation can be calculated by using the gradient formula when two points are given.
For the points (2,4) and (3,6)
Gradient =[tex]\frac{6-4}{3-2} =\frac{2}{1} =2.[/tex]
Option c .2 is the right option.
