单项选择题

有如下程序: Private Sub Command1_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.1
B.2
C.3
D.5