An equation where Y=6 could be represented on a graph where Y is on the vertical axis and X is on the horizontal axis as Select one: O a. a horizontal line form the origin with slope equal to 6. O b. a straight line along the vertical axis beginning at the point Y=6. O c. a single point (Y=6) and a horizontal line rightwards from that point. d. a vertical line from the origin with slope equal to 6.