Horizontal lines e and f are intersected by lines a and b. At the intersection of lines a and e, the uppercase left angle is 75 degrees. At the intersection of lines b and e, the uppercase right angle is 115 degrees. At the intersection of lines a and f, the bottom right angle is 75 degrees. Which lines are parallel? Justify your answer. Lines a and b are parallel because their alternate exterior angles are congruent. Lines a and b are parallel because their same side exterior angles are supplementary. Lines e and f are parallel because their alternate exterior angles are congruent. Lines e and f are parallel because their same side exterior angles are congruent.