#### Answer

The answer is 4

#### Work Step by Step

This is a problem about what it means graphically to add vectors. One procedure for adding vectors utilizes a graphical technique, in which the vectors to be added are arranged in a tail-to-head fashion.
The resultant vector is drawn from the tail of the first vector to the head of the last vector.
Looking at the four pictures given, the only one that has the resultant drawn from the tail of the first vector to the head of the last vector is the last picture, 4.