For the congruence of both triangles based on the AAS congruence theorem, it is required to have the additional information that: C. ∠A ≅ ∠O.
What is the AAS congruence Theorem?
The Angle-Angle-Side (AAS) congruence criterion assert that when two triangles share two congruent angles and a side adjacent to only one of these equal angles, the triangles are considered congruent to each other.
In the image shown, we see that:
DN ≅ TM [one pair of corresponding congruent sides]
∠D ≅ ∠T [one pair of corresponding congruent angles]
Therefore, for both triangles to be congruent by AAS congruence theorem, the additional information needed is: C. ∠A ≅ ∠O.