Given: ∠ABC is a right angle and ∠DEF is a right angle. Prove: All right angles are congruent by showing that ∠ABC ≅∠DEF.
What are the missing reasons in the steps of the proof?
A flow chart with 4 boxes that are labeled Given, A, B, C from left to right. Box Given contains angle A B C, angle D E F are right angles. Box A contains m angle A B C = 90 degrees and m angle D E F = 90 degrees. Box B contains m angle A B C = m angle D E F. Box C contains angle A B C is-congruent-to angle D E F.

A:
B:
C: