3x - 4
the y intercept is at -4 so has to be either d or b.
the slope is 3, which you can find by seeing how many units up the line goes when you go 1 unit to the right. there are points (0, -4) and (1, -1) on the graph, and we can see that when you go 1 unit to the right, the line goes 3 units up, so the slope is 3, which would make your answer d