Answer:
a.
Explanation:
The SAS (Side-Angle-Side) Congruence Theorem states that if two sides and the included angle in one triangle are congruent to two sides and the included angle in another triangle, then the two triangles are congruent.
The included angle in a triangle refers to the angle formed by two sides of the triangle that meet at a common vertex.
Therefore, pair "a" is the only set of triangles that demonstrates congruency of two sides and the included angle. In triangles ABC and TUV, side AB is congruent to side TU, side BC is congruent to side UV, and the included angle B is congruent to the included angle U.