单项选择题

把窗体的KeyPreview属性设置为True,然后编写如下过程: Private SubForm_KeyDown(KeyCode As Integer,Shift As Integer) PrintChr (KeyCode) End Sub Private Sub Form_KeyUp(KeyCode As Integer, Shift As Integer) PrintChr(KeyCode+2) End Sub 程序运行后,如果按“A”键,则输出结果为 ______。

A.A A
B.A B
C.A C
D.A D