[单项选择题] 编写如下事件过程： Private Sub Form MouseDown(Button As Integer，Shift As Integer，X As Single， Y As S

[单项选择题] 编写如下事件过程：

Private Sub Form MouseDown(Button As Integer，Shift As Integer，X As Single， Y As Single)

If Shift=6 And Button=2 Then

Print "BBBB"

End If

End Sub

程序运行后，为了在窗体上输出“BBBB”，应执行的操作为

A．同时按下Shift键和鼠标左键

B．同时按下Ctrl、Alt键和鼠标右键

C．同时按下Shift键和鼠标右键

D．同时按下Ctrl、Alt键和鼠标左键