有VB程序段如下：

s1 = Text1.Text

s2 = ""

For i = 1 To Len(s1)

    c = Mid(s1, i, 1)

    If c >= "0" And c <= "9" Then

        c = Chr((Asc(c) - Asc("0") + 1) Mod 10 + Asc("0"))

        s2 = s2 + c

    ElseIf c >= "A" And c <= "Z" Then

        c = Chr(Asc(c) + 32)

        s2 = c + s2

    End If

Next i

Text2.Text = s2

执行该程序段，在文本框Text1中输入“GoLand,19”，则文本框Text2中显示的内容为（    ）

A、lg20

B、lg210

C、210,dnalog

D、210,goland