The problem asks us to identify which of the given conditions (AAS, SSS, SAS, SSA) is *not* a sufficient condition for proving that two triangles are congruent.

1. Problem Description

The problem asks us to identify which of the given conditions (AAS, SSS, SAS, SSA) is *not* a sufficient condition for proving that two triangles are congruent.

2. Solution Steps

We need to consider each option to see if it guarantees congruence.

* AAS (Angle-Angle-Side): If two angles and a non-included side of one triangle are congruent to the corresponding two angles and non-included side of another triangle, then the two triangles are congruent.

* SSS (Side-Side-Side): If three sides of one triangle are congruent to the corresponding three sides of another triangle, then the two triangles are congruent.

* SAS (Side-Angle-Side): If two sides and the included angle of one triangle are congruent to the corresponding two sides and included angle of another triangle, then the two triangles are congruent.

* SSA (Side-Side-Angle): This case, where two sides and a non-included angle are known, is ambiguous. It does not guarantee congruence. This is sometimes referred to as the "ambiguous case".

Therefore, SSA is not a sufficient condition to prove triangle congruence.

3. Final Answer

D. SSA