Given: angles ABC is a right angle and angles DEF is a right angle. Prove: All right angles are congruent by showing that angles ABC congruent angles DEF.

What are the missing reasons in the steps of the proof?

A: Def. of right angle, def. of congruent, def. of equal, def. of 90°

B: Identity prop., reflexive prop., subtitution prop., symmetric prop.

C: Def. of congruent angles, def. of equal angles, substitution prop., symmetric prop.