下图所示对称结构的等代结构为（   ）

<img src、"http://sichuan.ouchn.cn/pluginfile.php/61594/question/answer/255204/9/246978/011-a.jpg" alt="" width="145" height="140">

<img src、"http://sichuan.ouchn.cn/pluginfile.php/61594/question/answer/255204/9/246979/011-b.jpg" alt="" width="145" height="140">

<img src、"http://sichuan.ouchn.cn/pluginfile.php/61594/question/answer/255204/9/246980/011-c.jpg" alt="" width="145" height="140">

<img src、"http://sichuan.ouchn.cn/pluginfile.php/61594/question/answer/255204/9/246981/011-d.jpg" alt="" width="145" height="140">