Which of the following theorems cannot be used to prove two lines are parallel? A If two lines are cut by a transversal so that a pair of same side interior angles are supplementary, then the lines are parallel.
B If two lines are cut by a transversal so that a pair of corresponding angles are congruent, then the lines are parallel.
C If two lines are cut by a transversal so that a pair of vertical angles are congruent, then the lines are parallel.
D If two lines are cut by a transversal so that a pair of alternate exterior angles are congruent, then the lines are parallel.