The answer is C.
Imagine you divide the shape into two triangles by putting a line from L to N. This would set angles K and M equal.
Then, you take 82+82 and subtract it from 360 to get 196. You do this because the total for angles inside a 4-sided shape is 360.
Divide 196 by 2, and you get angle measures of 98° for the two remaining angles.
Hope this helped!