JSFiddle - React, Tailwind, and code Playground

HTML

<div class="dropdown"> 
<select class="dropdown-select" onchange="if (this.value) window.location.href=this.value">
 <option value="#">Wybierz swoją szkółkę</option>
 <option value="http://xxx">1</option>
 <option value="http://xxx">2</option>
 <option value="http://xxx">3</option>
 <option value="http://xxx">4</option>
 <option value="http://xxx">5</option>
 <option value="http://xxx">6</option>
 </select>
</div>

CSS

select option:nth-child(5){
    display:none;
    color:red;
}