s = 0

For a =      To 8 Step 2

  s = s + a

Next a 

若要使语句s = s + a执行3次，则循环变量a初值为（   ）

Private Sub Command1_C1ick ( )

Dim a(9) As Integer

a(9)=Val(Text1.text)

For i=8 to 1 step -2

a(i)=a(i+1)/2

Next i

Text2.text=str(a(i))

End Sub

Private Sub Command1_Click()

Dim s As Integer, j As Integer

s = 0

For j = 1 To 10

  If j Mod 2 <> 0 Then

    s = s + j

  End If

Next j

Label1.Caption = Str(s)

End Sub

i = 1: j = 7: s = ""

key = 34

Do While i <= j

   m = (i + j) \ 2

   If key = a(m) Then

      s = s + "2": Exit Do    'Exit Do 表示退出循环

   ElseIf key < a(m) Then

      j = m - 1: s = s + "1"

Else

      i = m + 1: s = s + "3"

End If

Loop

Text1.Text = s

数组元素a(1)到a（9）的值依次为“15，26，34，47，53，59，60，72，85”。若该程序段执行后，文本框Text1中显示的内容可能是（  ）