To find the answer, all we need to do is to find the slope, which is rise/run. In this problem, the slope is negative, since it goes down from left to right. So we can throw A and B out. Now count how many units vertical and how many units horizontal from one point to the other. Or you can use the coordinates and figure it out since we got a nice point at the origin. I got 3 down and 4 right. So that would be -3/4. The answer is the last choice: y=-3/4x