Which of the following response(s) will lead to a null vector (?F=0)?

1.Adding a force 2 blocks up and another force ?13 blocks at 33.7° up and to the left.

2.Adding a force 2?2 blocks at 45° to the left and down and another force ?2 blocks at 45° to the left and up.

3.Adding af force three blocks to the right and another force nine blocks to the left.

4.Adding a force 15 blocks down and another force 15 blocks up and 3 to the left at an angle of 78.7° with the horizontal

5.Adding a force 3 blocks to the left.