title: Avoiding duplicate options in PHP form
body: <p>When I submit the form, it saves <code>InputField1</code> in my database, but the last saved selected <code>option</code> is shown twice in the list.</p>
  
  <pre><code>&lt;select name="&lt;?php echo $PLUGINMATRIX_NAME?&gt;InputField1" id="&lt;?php echo $PLUGINMATRIX_NAME?&gt;InputField1"&gt;
  &lt;option value="&lt;?php echo get_option($PLUGINMATRIX_NAME."InputField1");?&gt;"&gt;&lt;?php echo get_option($PLUGINMATRIX_NAME."InputField1");?&gt;&lt;/option&gt;
  &lt;option value="xvg"&gt;Verge&lt;/option&gt;
  &lt;option value="xrp"&gt;Ripple&lt;/option&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>How do I avoid showing duplicates in the above <code>select</code> after submitting the form?</p>