Given the line graphed, you can identify that it passes through this point:

The Point-Slope Form of the equation of a line is:

Where "m" is the slope of the line and this is a point on the line:

The Slope-Intercept Form of the equation of a line is:

Where "m" is the slope of the line and "b" is the y-intercept.
You can find the slope of the line using this formula:

Where these two points are on the line:

In this case, all the answer choices show that the slope is:

Then, you can substitute a point on the line graph into the equations provided in the answer choices and evaluate, until you find a true equation:
Using the equation given in Option A, you can substitute:

You get:




Hence, the answer is: Option A.