问题：

[单选]

public class X implements Runnable （ 
private int x； 
private int y；
 public static void main（String [] args） （ 
X that = new X（）； 
（new Thread（that）） . start（ ）； 
（new Thread（that）） . start（ ）； 
） 
public synchronized void run（ ） （ 
for （；；） （ 
 x++； 
y++； 
System.out.printIn（“x = “ +  x  + “， y = “ + y）； 
） 
） 
）  
What is the result？（）  

A .  An error at line 11 causes compilation to fail.
B .  Errors at lines 7 and 8 cause compilation to fail.
C .  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”）
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 twice （for example， “x=1， y=1” followed by “x=1， y=1”）
E .  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=2s， y=2”）