Note: I used the frames explained in the diagram post for all the questions in this game, so will start there.
For this question, the condition is O -- M. That's possible in either frame, so it's best to frame out what has to be true since this is a must be false question.
Frame 1:
P O M L __ __ __ (S T N in a cloud for the last spots)
Frame 2:
__ __ __ __ M T P (L -- N and L __ O / O __ L in a cloud for the first spots)
Either way, L can't be fifth, so the answer is (A).