1. The problem asks to identify the congruence criteria for the given triangles in part (a). 2. In part (a), triangles ABC and EFD are shown with two pairs of sides marked congruent: AB \cong EF and BC \cong FD. 3. To prove triangle congruence, common criteria include SSS (Side-Side-Side), SAS (Side-Angle-Side), ASA (Angle-Side-Angle), AAS (Angle-Angle-Side), and HL (Hypotenuse-Leg for right triangles). 4. Since only two pairs of sides are marked congruent, we need to check if the included angle between these sides is also congruent to apply SAS. 5. The problem does not provide angle information, so based on the given side congruences alone, the best we can say is that the triangles are congruent by the Side-Side-Side (SSS) criterion if the third sides are also congruent, or by Side-Angle-Side (SAS) if the included angles are congruent. 6. Without additional information, the congruence criterion cannot be definitively stated. Final answer: The triangles are congruent by the Side-Side-Side (SSS) or Side-Angle-Side (SAS) criterion if the third side or included angle is congruent respectively.