设已经在菜单编辑器中设计了窗体的快捷菜单，其顶级菜单为Bt，取消其“可见”属性，运行时，在以下事件过程中，可以使快捷菜单相应鼠标右键菜单的是
A．Private Sub Form_MouseDown(Button As Integer, Shift As Integer,_
X As Single, Y As Single)
If Button=2 Then PopupMenu Bt, 2
End Sub
B．Private Sub Form_MouseDown(Button As Integer, Shift As Integer, _
X As Single, Y As Single)
PopupMenu Bt
End Suh
C．Private Sub Form MouseDown(Button As Integer, Shift As Integer, _
X As Single, Y As Single)
PopupMenu Bt,0
End Sub
D．Private Sub Form_MouseDown(Button As Integer, Shift As Integer, _
X As Single, Y As Single)
If (Button=vbLeftButton) Or ( Button=vbRightButton) Then PopupMenu Bt
End Sub