The equation for slope-intercept form is y=mx+b, where m is the slope and b is the y-intercept.
You can eliminate answer choices B, C, and D, because the y-intercept doesn't fit. The y-intercept is where the line crosses the y-axis. There's no way it could be 6 or -1/4.
So now it's between A and D. In the image, the line is going down so we know the slope is negative, and slope is rise/run. It goes down about 1 and to the right about 4.
Meaning A is the only option that makes sense.