Hinge Theorem:
For two triangles with two equal sides, the angle opposite the larger non-equal side is larger than the angle opposite the smaller non-equal side, so A cannot be true because <LOM is opposite a bigger side than <NOM.
Isosceles triangle:
If two sides of a triangle are equal, then the angles opposite those sides are equal. <MLO and <LMO are both opposite sides of equal length (9), so B is true.
C is not true, because just because angles are opposite sides of equal length in two different triangles it doesn't mean those angles are equal.
The circumcenter of a triangle will lie outside the triangle if it is an obtuse triangle. Both triangles are acute isosceles triangles, do D is not true.