The equation which would enable us find the measure of angle M is obtained as follows:
- Recall that the opposite angles of a parallelogram are supplementary (that is, they sum up to 180 degrees)
- Now, we will have to sum up the angles L and M and equate to 180 degrees (because these two angles are opposite each other in the parallelogram given)
Thus:

Thus, the above expression will enable us solve for the value of z, which we will thereafter use to obtain the measure of angle M.
Therefore, the correct answer is : option D