编写如下事件过程：
Private sub sub1 (ByVal x1 As String, y1 As String)
Dim xt As String
Dim i As Integer
i = Len(x1)
Do While i＞= 1
xt = xt + Mid(x1, i, 1)
i=i-1
Loop
y1 = xt
End Sub
Private Sub Form Click（　）
Dim s1 As String, s2 As String
s1= "teacher"
sub1 s1, s2
Print s2
End Sub
程序运行后，单击窗体，则窗体上显示的内容是

A:rehcaet B:tahreee C:themee D:eerthea

编写如下事件过程： Private sub sub1 (ByVal x1 As String, y1 As String) Dim xt As String Dim i As Integer i = Len(x1) Do While i＞= 1 xt = xt + Mid(x1, i, 1) i=i-1 Loop y1 = xt End Sub Private Sub Form Click（　） Dim s1 As String, s2 As String s1= "teacher" sub1 s1, s2 Print s2 End Sub 程序运行后，单击窗体，则窗体上显示的内容是

A:rehcaet B:tahreee C:themee D:eerthea