JSFiddle - React, Tailwind, and code Playground

HTML

<select>
        <option value="English">English</option>
        <option value="English1">English</option>
        <option value="English2">English2</option>
        <option value="Geology">Geology</option>
       
        <option value="Geology1">Geology</option>
        <option value="Information Technology">Information Technology</option>
        <option value="Music">Music</option>
        <option value="hello">Music</option>
        <option value="Zoology">Zoology</option>
</select>

JavaScript

label = new Object();
$('select option').each(function(){
    if(label[$(this).value()] != 1)
        label[$(this).value()] = 1;
    else $(this).remove();
 });