What is the missing step in the given proof? given: ab bd and ab cd

Prove: PCQ is complementary to ABC. A. PCQ and ACP are supplementary by the Linear Pair Theorem.

B. For parallel lines cut by a transversal, corresponding angles are congruent, so A. CB PCQ.

C. OCP BCD by the Vertical Angles Theorem.

D. For parallel lines cut by a transversal, corresponding angles are congruent, so OCP ABC.

E. For parallel lines cut by a transversal, corresponding angles are congruent, so OCA CBD.