Which of the following are exterior angles? Check all that apply.
6.5
A. 26
B. 22
C. 25
D. 23
E 24
F. 21

Ok, so:
Here we have the next figure:
The external angles, are angles which are outside the figure. (Triangle)
In this case, as you can see in the graph, these angles are outside the triangle.
So, 2,4 and 6, are the external angles.