5. if p || q, which pair of angles must be congruent?
1 and 8
2 and 5
4 and 6
7 and 8

I think the correct answer from the choices listed above is the first option.  If p || q, the pair of angles that must be congruent would be angles 1 and 8. These angles are called alternate exterior angle.  The pairs of angles on opposite sides of the transversal but outside the two lines are called Alternate Exterior Angles.