S stands for 'side'
A stands for 'angle'
SAS means side angle side meaning 2 sides and 1 angles are congruent so
SSS means side side side, and we aren't given 3 sides so this is out
AA means angle angle where 2 angles are known and since they are congruent, the triangles are similar thiis is correct
SAS means that 2 sides and 1 angles are congruent which is false since we dont' known 2 sides
answer is AA