1. public class X implements Runnable（ 
2. private int x； 
3. private int y； 
4.   
5. public static void main（String[]args） 
6. X that = new X（）； 
7. （new Thread（that））.start（）； 
8. （new Thread（that））.start（）； 
9. ） 
10.   
11. public void run（）  （ 
12. for （；；）  （ 
13. x++； 14. y++； 
15. System.out.printIn（“x=” + x + “， y = ” + y）； 
16.     ）
17. ）
What is the result？（）

A. Errors at lines 7 and 8 cause compilation to fail.
B. The program prints pairs of values for x and y that might not always be the same on the same line （for example， “x=2， y=1”）.
C. The program prints pairs of values for x and y that are always the same on the same line （for example， “x=1， y=1”. In addition， each value appears twice （for example， “x=1， y=1” followed by “x=1， y=1”）.
D. The program prints pairs of values for x and y that are always the same on the same line （for example， “x=1， y=1”. In addition， each value appears only for once （for example， “x=1， y=1” followed by “x=2， y=2”）.