class Order2 implements Runnable { 6. public void run() { 7. for(int x = 0; x 〈 4; x++) { 8. try { Thread.sleep(100); } catch (Exception e) { } 9. System.out.print("r"); 10. } } 11. public static void main(String [] args) { 12. Thread t = new Thread(new Order2()); 13. t.start(); 14. for(int x = 0; x 〈 4; x++) { 15. // insert code here 16. System.out.print("m"); 17. } } } 哪一个插入到第15行,最有可能产生输出 rmrmrmrm ?()