单项选择题

下列程序的执行结果为 Private Sub Command1_Click() Dim FirStr As String FirSt="abcdef" Print Pat(FirStr) End Sub Private Function Pat(xStr As String) As String Dim tempStr As String,strLen As Integer tempStr="" strLen=Len(xStr) i=1 Do While i<=Len(xStr)-3 tempStr=tempStr+Mid(xStr,i,1)+Mid(xStr,strLen-i+1,1) i=i+1 Loop Pat=tempStr End Function

A.abcdef
B.afbecd
C.fedcba
D.defabc