10. In the figure to the right, AB is parallel to CD. Which statement proves that 23 = 277
A. If two parallel lines are cut by a transversal, the alternate interior angles are congruent.
B. If two parallel lines are cut by a transversal, the alternate exterior angles are congruent.
.If two parallel lines are cut by a transversal, the corresponding angles are congruent.
D. If two parallel lines are cut by a transversal, the vertical angles are congruent.