程序代码如下，当单击窗体上的Command1控件时，窗体上显示的结果是( )。
Private Sub Command1_Click()
Dim i As Integer，a(9)As Integer
For i=9 To 0 Step-1
a(i)=10-i
Next i
Print a(2); a(5)；a(8)
End Sub

A．Static arr1(3)
arr1(1)=100
arr1(2)="Hello"
arr1(3)=123.45
B．Dim arr2() AsInteger
Dim size As Integer
Private Sub Command2_Click ()
size=InputBox("输入：")
ReDim arr2(size)
……
EndSub
C．Option Base 1
Private Sub Command3 Click()
Dim art3(3) As Integer
……
End Sub
D．Dim n As Integer
Private Sub Command4 Cliok()
Dim arr4(n)As Integer
……
End Sub

A．List
B．ListCount
C．ListIndex
D．Columns