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Shift键和鼠标右键
C.同时按下Ctrl、Alt键和鼠标左键
D.同时按下Ctrl、Alt键和鼠标右键