What is the answer to this question smart people

SAS

Explanation:
To prove congruency by:
1- SSS:
Each side in the first triangle should be congruent to the corresponding side in the second triangle.
2- SAS:
Two sides and the INCLUDED angle between them in one triangle should be congruent to the corresponding two sides and the INCLUDED  angled in the second. If the angle is not included between the two sided, SAS becomes invalid
3- AAS:
Two angles and one side in one triangle should be congruent to the corresponding two angles and side in the other triangle

In the given triangles we have:
AS = KS
angle 6 = angle 9
SC is a common side between the two triangles

We can note that:
angle 6 is the angle included between AS and SC in the first triangle
angle 9 is the angle included between KS and SC in the second triangle

Therefore:
We have two sides and an included angle in the first triangle congruent to the corresponding two sides and the included angle in the second.

Therefore, we can prove the two triangles to be congruent using SAS postulate

Hope this helps :)