Answer:
D. For parallel lines cut by a transversal, corresponding angles are congruent, so ∠OCP ≅ ∠ABC.
Explanation:
Since we need to show the connection of the proof from m∠OCP + m∠PCQ = 90° by the transitive property of equality to the definition of congruent angles, m∠OCP= m∠ABC, letter D which states that For parallel lines cut by a transversal, corresponding angles are congruent, so ∠OCP ≅ ∠ABC is the only statements that fits to what we need to show.