Fill in the blank with the phrase that makes the proof statement true.
Lines m and n are parallel. Angle 1 is congruent to angle 2 by the Corresponding Angles Postulate. Angle 1 is congruent to angle 3 because they are vertical angles. _ by the Transitive Property.
A. Angle 2 is congruent to angle 3
B. Angle 3 is supplementary to angle 1
C. Angle 2 is congruent to angle 1
D. Angle 1 is complementary to angle 2