The equation of the line through ab *write your answer in slope-intercept form

Sounds as tho' you have a line going thru two points, A and B, but you have not shared those points.  Please do so.

But we can assume that A:(a,b) and B:(c,d), find the slope and then write the equation of the line thru points A and B:
          
          d - b
m =
          c - a
                                                                d - b
then the equation of the line is   y-d = (x-c)
                                                                c - a

Please ensure that you are sharing all of the info given (e. g., the coordinates of the points A and B).

I'm sure the answer is a