The SAS (Side-Angle-Side) criterion can be used to prove the similarity of two triangles by the following statement:
If two corresponding side lengths of each triangle are proportional, and the included angle between those sides is equal, then the two triangles are similar.
This means that if you have two pairs of sides from each triangle that are in proportion (for example, if side AB of triangle ABC is proportional to side DE of triangle DEF, and side AC is proportional to side DF), and the angle formed between those two sides in both triangles is the same (angle A in triangle ABC is equal to angle D in triangle DEF), then you can conclude that the two triangles are similar.
Thus, the first response option you provided succinctly captures this concept:
If two corresponding side lengths of each triangle are given and are proportional, with a proven included angle measure, the triangles are similar.