窗体上有一个名为Command1的命令按钮，并有如下程序：
Private Sub Command1_Click()
Dim a As Integer,b As Integer
a=13
b=27
Print Fun(a,b)；a;b
End Sub
Private Function Fun(ByVal a As Integer,b As Integer) As Integer
a=a Mod 5
b=b\5
Fun=a
End Function
程序运行时，单击命令按钮，则输出的结果是______。

A) Private Sub Form_Mouse Down(Button As Integer,Shift As Integer,_X As Single,
Y As Single)
If Button=2 Then PopupMenu a1,2
End Sub
B) Private Sub Form_Mouse Down(Button As Integer,Shift As Integer,_X As Single,
Y As Single)
PopupMenu a1,0
End Sub
C) Private Sub Form_Mouse Down(Button As Integer,Shift As Integer,_X As Single,
Y As Single)
PopupMenu a1,2
End Sub
D) Private Sub Form_Mouse Down(Button As Integer,Shift As Integer,_X As Single,
Y As Single)
If(Button=vbLetfButton) Or(Button=vbRightButton) Then PopupMenu a1
End Sub

A) 若d盘根目录下无Test.txt文件，则该语句创建此文件
B) 该语句打开d盘根目录下一个已存在的文件Test.txt，之后就可以从文件中读取信息
C) 执行该打开文件语句后，可以用Line Input#语句按行读取数据
D) 用Line Input语句读出数据时，遇到回车符则结束读取