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.1
B.2
C.3
D.5