Lines e and f are intersected by lines a and b. At the intersection of lines a and e, the uppercase right angle is 110 degrees. At the intersection of lines b and e, the uppercase right angle is 110 degrees. At the intersection of lines b and f, the bottom right angle is 80 degrees. Which lines are parallel? Justify your answer.

Lines a and b are parallel because their corresponding angles are congruent.
Lines a and b are parallel because their same side exterior angles are congruent.
Lines e and f are parallel because their corresponding angles are congruent.
Lines e and f are parallel because their same side exterior angles are supplementary.