设有如下程序： import java.util.*; public class Sun public static void main (String args[ ]) int score; String a; Random r=new Random (); score=r.nextInt (4)+5; switch(score) case 0: a= E ; break; case 1: a= D ; break; case 2: a= C ; break; case 3: a= B ; break; default: a= A ; System.out.println (
A．;
程序运行的结果是( )。A) a="A"
B．a="E" a="A"
C．a="E"
D．a="C"