Do same-side interior angles have to be on the same (in this case) horizontal line? to specify, does it always have to be ab, or can it be ad. i’m doing a transversal project at the moment, and am very confused.

The line plot below represents the number of letters written to overseas pen pals by the students at the waverly middle school.each x represents 10 students. how many students wrote more than 6 and fewer than 20 letters. a.250 b.240 c.230 d.220