Okay, here we have this:
Considering the provided graph, we are going to calculate the requested equation, so we obtain the following:
So let's remember that to obtain the equation of a straight line of the form y=mx+b, we need to know the slope and the y-intercept, so we have:
Slope=(y2-y1)/(x2-x1)
Slope=(3-2)/(3-0)
Slope=1/3
And we can see that the y-intercept is y=2, so we finally get the following equation of the line:
y=mx+b
y=1/3x+2
Finally we get that the correct answer is the third option.