Given a line of best fit that was drawn for 8 points, you need to remember that a line of best fit is drawn on a Scatter Plot to best represent the relationship of the data.
Since the line drawn approximates the relationship, it might not pass through all the points plotted on the Scatter Plot.
Therefore, if there are 8 points on the Scatter Plot, you should try to draw a line that passes through all the points you can, and the number of points above it and below it must be approximately equal. However, it might not pass through a point, but approximately close to it.
Then, if there are "n" points, the maximum number of points that may not actually be on the line is "n".
Hence, the answer is: Option D.