The two given triangles have two sides in the first equal to two sides in the second and an angle in the first equal to an angle in the second.
This means that we're looking for congruent triangles using SAS rule, this means that two sides and the included angle in one triangle are equal to the CORRESPONDING two sides and the included angle in the second triangle.
For the two given triangles:
JK = LK
NK = MK
angle JKN = angle LKM
Following this sequence, we can say that:
triangle JKN is congruent to triangle LKM
Checking the choices, we will find that the correct choice is: D
