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 Singl 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 Singl PopupMenu Bs End Sub
C．Private Sub FOrm_MouseDown(Button As Integer，Shift As Integer，- X As Single，Y As Singl PopupMenu Bs，0 End Sub
D．Private Sub Form_MouseDown(Button As Integer，Shin As Integer，- X As Single，Y As Singl If(Button=vbLeftButtoOr(Button=vbRightButtoThen PopupMenu Bs End Sub