When using a line graph, why is it inportant to only graph 1 - 3 series of data? . a. a line graph in microsoft excel will not allow you to graph more than 3 series of data.. b. it will not show changes over time of you use more than 3 series of data.. c. the lines are too thick to use more than 3 series.. d. more than 3 series of data causes too many lines on the graph, which makes ti confusing to read.