某算法程序段如下：

Dim s1 As String, s2 As String, ch As String

Const code = "@*()^&#"

s1 = Text1.Text

For i = 1 To Len(s1)

    ch = Mid(s1, i, 1)

    If ch >= "a" And ch <= "z" Then

        t = (Asc(ch) - 65 + i) Mod 7

        s2 = Mid(code, t + 1, 1) + s2

    Else

        s2 = s2 + ch

    End If

Next i

Text2.Text = s2

若 text1 中输入字符“AbCd”，则 text2 中输出的是 （     ）

A、 AC^@

B、 ^@AC

C、 ^(@&

D、A^C@