At this Games, all athletes participating in the freestyle competition participated in the breaststroke competition. Which of the following statements can be added to introduce "Some athletes participating in the butterfly stroke did not participate in the freestyle competition"? ['All athletes participating in the butterfly stroke also participated in the breaststroke.', 'Some athletes participating in the breaststroke competition participated in the butterfly stroke competition.', 'Some athletes who did not participate in the breaststroke competition participated in the butterfly stroke.', 'Some athletes who did not participate in the butterfly stroke did not participate in the breaststroke.']