Six puppies- K, L, M,S, T, U- must each be scheduled for examination by a veterinarian. The puppies are to be examined one at a time is six consecutive time slots on the same day according to the following conditions: M cannot be examined immediately before or immediately after S. L must be examined immediately before U. K must be examined fourth. Which of the following is an acceptable examination schedule for the puppies, in order from first examined to last examined?