单项选择题

有如下程序:   Private Sub Commandl_Click( )     a$="A WORKER IS HERE"     x=Len(a$)     For i=1,To x-1       b$=Mid$(a$,i,3)       If b$="WOR" Then S=S+1     Next     Print S   End Sub   单击命令按钮,程序运行结果为( )。

A. const,break,default
B. long,void,using
C. virtual,extern,include
D. try,throw,this