單選題：11. class payload { 
12. private int weight; 
13. public payload（int wt） { weight = wt; } 
13. public void setweight（mt w） { weight = w; } 
15. public string tostring { return integer.tostring（weight）; } 
16. } 
17. 
18. public class testpayload { 
19. static void changepayload（payload p） {
20. /* insert code here */
21. } 
22. 
23. public static void main（string args） { 
24. payload p = new payload（）; 
25. p.setweight（1024）; 
26. changepayload（p）; 
27. system.out.println（」the value of p is 「+ p）; 
28. } 
29. } 
Which statement, placed at line 20, causes the code to print 「the value of p is 420.」?（） 
A、 p.setweight（420）;
B、 p.changepayload（420）;
C、 p = new payload（420）;
D、 payload.setweight（420）;
E、 p = payload.setweight（420）;
F、 p = new payload（）; p.setweight（420）;

答案：A