Answer:
A. SSS
Step-by-step explanation:
∆ABC has shown above has two given sides indicated, AB and AC, which are congruent to the corresponding two sides l, DC and DB, of ∆DCB.
Also, their third side is also congruent since they share a common side, side BC.
This means that the three sides of ∆ABC is congruent to the three corresponding sides of ∆DCB.
Therefore, ∆ABC is congruent to ∆DCB by the Side-Side-Side Congruence Theorem, which holds that of the three sides of one triangle is congruent to the three corresponding sides of another, then both ∆s are congruent.