设有如下程序； Private Sub Form_ Load()ShowText1.Text = " "Text1.SetFocus End Sub Private Sub Form_ MouseUp (Button As Integer, Shift As Integer, X As Single, Y As Single)Print “程序设计” End Sub Private Sub Text1_ KeyDown (KeyCode As Integer, Shift As Integer)Print "Visual Basic" End Sub程序运行后，如果在文本框中输入字母a(即直接按a键)，然后单击窗体，则在窗体上显示的内容是______ 。

A．Visual Basic

B．程序设计

C．Visual Basic程序设计

D．A程序设计