注：BMI指数的计算公式为：BMI=体重（千克）除以身高（米）的平方（kg/m2）。 BMI<18.5为偏瘦（表明营养不足）；BMI=18.5～24.9为体重正常；BMI=25～29.9为超重；BMI>30为肥胖。

该VB应用程序的代码如下：

Dim stuBMI(1 To 55) As Single

Dim stuName(1 To 55) As String

Private Sub Command1_Click()

    Dim k As Integer, i As Integer, j As Integer

    Dim t1 As Single, t2 As String

    Dim Results As String

    For i = 1 To 54        

        For j = i + 1 To 55

            If stuBMI(j) < stuBMI(k) then      ②    

        Next j

        If  k<>I  Then  

            t1 = stuBMI(i): stuBMI(i) = stuBMI(k): stuBMI(k) = t1

            t2 = stuName(i): stuName(i) = stuName(k): stuName(k) = t2

        End If

    Next i

List1.AddItem "姓名" + vbTab + "BMI指数" + vbTab + "结果"  

    For i = 1 To 55

        If stuBMI(i) < 18.5 Then

            Results = "偏瘦"

        ElseIf stuBMI(i) >= 18.5 And stuBMI(i) < 25 Then

            Results = "正常"

        ElseIf stuBMI(i) >= 25 And stuBMI(i) < 30 Then

            Results = "超重"

        Else

            Results = "肥胖"

        End If

        List1.AddItem stuName(i) + vbTab + str(stuBMI(i)) + vbTab + Results

    Next i

End Sub

Private Sub Form_load()

    Dim conn As New ADODB.Connection

    Dim rs As New ADODB.Recordset

    Dim strSQL As String

    Dim i As Integer

    conn.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + App.Path + "\Student.accdb"

    conn.Open

    strSQL = "SELECT * FROM Student"

    Set rs.ActiveConnection = conn

    rs.Open strSQL

    i = 0

    Do While Not rs.EOF

        i = i + 1

        stuName(i) = rs.Fields("StuName")

        stuBMI(i) = Round(rs.Fields("Weight") / rs.Fields("height") ^ 2, 1)

        rs.MoveNext

    Loop

    rs.Close

    conn.Close

    Set rs = Nothing

    Set conn = Nothing

End Sub

Dim a(1 To 10) As Integer

Private Sub Command1 Click()

Dim i As Integer, j As Integer, x As Integer p = True

i = 1

    Do While i <= 9 And p p= False

    For j = 10 To i + 1 Step -1

        If  Then    '①

            k = a(j): a(j) = a(j - 1): a(j - 1) = k: p = True

        End If

    Next j

    i = i + 1

Loop

For i = 1 To 10

    List2.AddItem Str(a(i)) Next i

End Sub

Private Sub Form_Load()

Dim i As Integer

List1.Clear

Randomize         '初始化随机函数 Rnd

For i = 1 To 10

    a(i) =     '②

List1.AddItem

Str(a(i))

Next i

End Sub

①{#blank#}1{#/blank#} ②{#blank#}2{#/blank#} 

Dim a(1 To 100) As String '依次存放100 个随机字符串

Dim b(1 To 100) As Integer '依次存放每个字符串的权值

Private Sub Command1_Click() '产生100 个随机字符串

Dim i As Integer, k As Integer, t As Integer, x As Integer

Randomize

For i = 1 To 100

k = Int(Rnd * 10 + 1) : t = 0  'k 表示第i 个字符串的长度

Do While t < k '通过循环依次产生第i 个字符串a(i)的k 个字符

If Int(Rnd * 2 + 1) = 1 Then '产生一个小写字母的ASCII 码值

x = Asc("a") + Int(Rnd * 26)

Else

x = Asc("A") + Int(Rnd * 26) '产生一个大写字母的ASCII 码值

End If

                '①

If b(i) < x Then b(i) = x

t = t + 1

Loop

List1.AddItem a(i)

Next i

End Sub

Private Sub Command2_Click() '对100 个字符串按字符串权值降序排序

Dim i As Integer, j As Integer, y As Integer

Dim s As String

For i = 1 To 99

k = i

For j = i + 1 To 100

    '②

Next j

If k <> i Then

s = a(k): a(k) = a(i): a(i) = s

y = b(k): b(k) = b(i): b(i) = y

End If

Next i

For i = 1 To 100

List2.AddItem a(i)

Next i

End Sub

①{#blank#}1{#/blank#} ②{#blank#}2{#/blank#} 

For i= n To 2 step -1

  For j =

    If a(j) > a(j + 1) Then

      t = a(j): a(j)=a(j + 1): a(j + 1)=t

    End If

  Next j

Next i

方框中的代码会是以下四句中的某一句：

① 1 To i -1                ② n–1 To i Step -1

③ 1 To n - i                ④ n–1 To n - i+1 Step-1

正确的选项是（    ）