Select the correct answer Given AD BC Prove DC 6 units A 6 units D Statements AD BC ZDAC AC AC ZDCA C ZBAC DC BA DC BA DC 6 units Which step is missing given ZBCA alternate interior angles theorem reflexive property of congruence alternate interior angles theorem B O A ADAC O B ADCA O c ADCA O D ADAC Reasons CPCTC definition of congruent sides substitution property of equality ABCA by SAS ABCA by ASA ABCA by SAS ABCA by ASA