Respuesta :

If ΔABC = ΔADC, then B. BC = DC by CPCTC.

CPCTC is an acronym for Corresponding Parts of Congruent Triangles are Congruent. 

Answer choice C and D are not appropriate answers because they are not the corresponding angles of the triangles. 
Answer choice A is not the appropriate answer because although the statement is true, CPCTC would not be the correct reasoning.