单项选择题

在窗体中添加—个名称为Command1的命令按钮,然后编写如下代码:     Function F(a As Integer) b=0 Static c b=b+1 C=c+1 F=a+b+c End Function Private Sub Command1_Click( ) Dim a As Integer Dim b As Integer a=2 For i=l To 3 b=F(a) Print b Next i End Sub 程序运行后,如果单击按钮,则在窗体上显示的内容是

A.4 4 4
B.4 5 6
C.5 6 7
D.5 5 5