单项选择题

执行下列程序后,鼠标单击窗体,输出结果为
Private Sub Form_Click()
  Print"Click":
End Sub
Private Sub Form_MouseDown(Button As Integer,Shift_As Integer,X As Single,Y As Single)
  Print"Donw"
End Sub
Private Sub Form_MouseUp(Button As Integer,Shift_As Integer,X As Single,Y As Single)
  Print"Up"
End Sub

A.DownUpClick
B.CfickDownUp
C.DownClickUp
D.UpDownClick