count = 0

For i = 1 To 20

    a(i) = Int(Rnd ∗ 100) + 1

Next i

For i = 1 To 20

Next i

For i = 1 To 100

    If b(i) <> 0 Then count = count + 1

Next i

Label1.Caption= "不重复数字个数" + Str(count)

为实现上述功能,则程序①处应填入的语句为（   ）

Private Sub Command1_Click()

    Dim s As String, s1 As String, c As String

    s = Text1.Text

    For i = 1 To Len(s)

        c = Mid(s, i, 1)

        s1 =    ⑴   

        For j =    ⑵   

            If c <> Mid(s, j, 1) Then

                s1 = s1 + Mid(s, j, 1)

            End If

        Next j

           ⑶    

    Next i

Text2.Text = s

End Sub

s = "A-b2c " ; ch = ""

list=[4 , 3 , 1 , 5 ,2]

for i in range(1en( s)):

    if "A " <= s [i] <= "Z " :

        ch = ch + chr (ord(s [i]) + list[i])

    elif "a " <= s [i] <= "z " :

        ch = ch + chr (ord(s [i]) - list[i])

    else:

        ch= s [i]+ch

print(ch)

该程序运行后，输出的结果是（   ）