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Bs，取消其“可见”属性，
运行时，在以下事件过程中，可以使快捷菜单响应鼠标右键菜单的是

A．Private Sub Form_Mouse Down(Button As Integer，Shift As Integer，-

　　　　　X As Single，Y As Single)

　　If Button=2 Then PopupMenu Bs，2

　　End Sub

B．Private Sub Form_MouseDown(Button As Integer，Shift As Integer，-

　　　　　　　　X As Single，Y As Single)

　　　　PopupMenu Bs

　　End Sub

C．Private Sub FOrm_MouseDown(Button As Integer，Shift As Integer，-

　　　　　　　X As Single，Y As Single)

　　　　PopupMenu Bs，0

　　End Sub

D．Private Sub Form_MouseDown(Button As Integer，Shin As Integer，-

　　　　　　　X As Single，Y As Single)

　　　　If(Button=vbLeftButton)Or(Button=vbRightButton)Then PopupMenu Bs

　　End Sub