B.) is the correct answer.
In slope intercept form, y=mx+b, the x is the slope and b the y-intercept.
In this case, the y-int is 0, so there is no need to put it.
That means it's wither B or C
Slope is also know as rise over run.
If you check B's slope of 4, by going up 4 and over 1, then you know it's the right answer.
Hope this helps!