Stefan was able to map \triangle ABD△ABDtriangle, A, B, D onto \triangle ABC△ABCtriangle, A, B, C. Stefan concluded: "I was able to map \triangle ABD△ABDtriangle, A, B, D onto \triangle ABC△ABCtriangle, A, B, C using a sequence of rigid transformations, so the figures are congruent." What error did Stefan make in his conclusion? Choose 1 Choose 1 (Choice A) A Stefan didn't use only rigid transformations, so the figures are not congruent. (Choice B) B It's possible to map \triangle ABD△ABDtriangle, A, B, D onto \triangle ABC△ABCtriangle, A, B, C using a sequence of rigid transformations, but the figures are not congruent. (Choice C) C There is no error. This is a correct conclusion.