Answer: SAS
Step-by-step explanation:
SAS = side angle side
The tickmarks tell us which sides are congruent to one another. This forms one S of SAS.
The other S would be the shared overlapping sides between the triangles. We're using the reflexive property here.
The marked angles in red are congruent to one another, which refers to the 'A' in SAS. We have two pairs of congruent sides, and a pair of congruent angles between those sides. This allows us to use the SAS rule.
SSS can't be used since we don't know anything about the third pair of sides.