Answer:
SSS - Two triangles have to have 3 congruent pairs of sides.
ASA - Two triangles have to have 2 congruent pairs of angles with an included congruent pair of sides.
SAS - Two triangles have to have 2 congruent pairs of sides with an included congruent pair of angles.
AAS - Two triangles have to have 2 pairs of congruent angles with a non-included congruent pair of sides.