Sides JK and LK are equal, they are the two sides in red:
Also sides JM and LM are equal, they are the two sides in blue:
So far, the two triangles have two equal sides.
And since they share the middle side, shown in green:
The triangles JKM and LKM are equal because all of their sides are equal.
Thus, the answer is:
D. Side-Side-Side
