Answer:
Mark angles C and F as congruent.
Step-by-step explanation:
Angle-Angle-Side (AAS) Congruence Theorem
If any two angles and the non-included side of one triangle are congruent to the corresponding parts of another triangle, the triangles are congruent.
The given triangles have one corresponding angle and one corresponding side marked as congruent.
To satisfy AAS congruency, another pair of corresponding angles need to be marked as congruent.
As an included side is the side between two angles, we cannot mark angles A and P as congruent, as this would not satisfy AAS congruency since sides AB and PD would be the included sides.
Therefore, to make triangle ABC congruent to triangle PDF by AAS, mark angles C and F as congruent.