2-15的练习题为啥不一样

<table>

<tr>

<td> 

<select size="9">

<option selected="">请选择：</option>

<optgroup label="水果">

<option value="apple">苹果</option>

<option value="peach monkey">猕猴桃</option>

<option value="xinzi">杏子</option>

</optgroup>

<optgroup label="蔬菜">

<option value="tomato">西红柿</option>

<option value="carribage">白菜</option>

<option selected="" value="cat">油麦菜</option>

</optgroup>

  </td>

</tr>

</table>