Well, there's a lot of ways you could do this. Because it's multiple choice, you can just pick a pair of points and whatever equation it works in, that's your answer. In this case, it's the third one down.
If you didn't have multiple choice you would use these two formulas:
m = (y2 - y1)/(x2-x1)
y - y1 = m (x - x1)
