We would like to remove the Wordpress Admin Dashboard HTML Tab.

Please see attached image for additional clarification.

What we need is from the programmer is to tell us which file in the wp-admin contains the codes.

All we are looking for is the file path that will take away the tab.
Please see code below.
<div id="postdivrich" class="postarea">

<div id="editor-toolbar">
<div class="zerosize"><input accesskey="e" type="button" onclick="switchEditors.go('content')" /></div>
<a id="edButtonHTML" class="active hide-if-no-js" onclick="switchEditors.go('content', 'html');">HTML</a>
<a id="edButtonPreview" class="hide-if-no-js" onclick="switchEditors.go('content', 'tinymce');">Visual</a>

We would like to remove following code: <a id="edButtonHTML" class="active hide-if-no-js" onclick="switchEditors.go('content', 'html');">HTML</a>