Below are \triangle ABC△ and \triangle DEF△DEFtriangle, D, E, F. We assume that AB=DEAB=DEA, B, equals, D, E, BC=EFBC=EFB, C, equals, E, F, and AC=DFAC=DFA, C, equals, D, F.




Answer:
Step-by-step explanation:
Justification of step 1 is based on the congruence of segments AB and DE.
Therefore correct choice is the first one: