Supplementary angles are angles that together, for an angle of 180°. Straight lines are also 180°, so what you need to look for in this exercise are angles, next to eachother, on the same straight line.
those are:
1,2
1,4
2,3
5,6
5,8
6,7
7,8
3,4
so the right answers are option 1 and 2