Given: js ≅ ks; ∠1 ≅ ∠8; ∠2 ≅ ∠7

which postulate justifies that δjas ≅ δ kcs?
a) aas correct answer
b) asa
c) sas
d) sss

Triangle ΔJAS:
we know side JS, angle 1 and angle 2 

Triangle ΔKCS:
we know side KS, angle 7 and angle 8

For each of these triangles we know one side and two angles.

In the possible answers A stands for angle and S stands for side.
So the correct answer would be something that involves one S and two As. That could be either a) or b). We choose a) because we have two angles and a side opposite to one of them. We would choose b) if the side was between these two angles.