Answer
By SAS, $\triangle CAB \cong \triangle DAB$
Work Step by Step
Side: It is given in the question that $\overline{AC} \cong \overline{AD}$
Angle: It is given in the question that $\angle CAB \cong \angle DAB$
Side: Both triangles share the side $\overline{AB}$, so by identity, $\overline{AB} \cong \overline{AB}$
Therefore, by SAS, $\triangle CAB \cong \triangle DAB$