Answer: -2 which is choice A
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Each time you move to the right 1 unit along the x axis, you will move 2 units down on the y axis along the diagonal line.
The rise is -2 indicating a drop of 2 for each time the run is 1
rise/run = -2/1 = -2
An alternative is to use the slope formula m = (y2-y1)/(x2-x1) and you'll get the same answer. You can pick any two points on the line.