What else would need to be contruent to show that ABC=DEF by the AAS theorem

The correct option is Option B: ∠C≅∠F
Two triangles are said to be congruent, if the triangles are of the same size and shape i.e. two triangles have the same side and angle also.
AAS theorem i.e. Angle-Angle-Side theorem states that two triangles are congruent if two angles and non included sides of one triangle are equal to the corresponding two angles and non included sides of another triangle, then two triangles are congruent.
Here, in the figure, two triangles are ΔABC and ΔDEF
it is given that ΔABC ≅ ΔDEF
these two triangles are congruent by AAS theorem,
∠A≅∠D
AB=DE
So here, one triangle and one side are already congruent between the two triangles.
For AAS theorem to be proved, there is a need for one angle which is not in touch with AB and ED in their respective triangles.
So, in triangle ΔABC, ∠C is not in touch with AB.
And in triangle ΔDED, ∠F is not in touch with DE.
So, ∠C≅∠F
Therefore The correct option is Option B: ∠C≅∠F
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