【加试题】某Visual Basic程序如下：（   ）

Private Sub Command1Click()

  Dim a(-1 To 8) As Integer

  Dim i As Integer

  For i = -1 To 8

    a(i) = i * i

  Next i

  List1.AddItem Str (a(i))

End Sub

运行程序，单击命令按钮Command1后，出现的错误提示为

A：下标越界

B：子程序或函数未定义

C：溢出

D：类型不匹