JSFiddle - React, Tailwind, and code Playground

HTML

<select name="tree" id="sel_cat">
    <option>All</option>
    <option value="1">&nbsp; Activity</option>
    <option value="2">&nbsp; Alert</option>
    <option value="3">&nbsp; &nbsp; Lead</option>
    <option value="4">&nbsp; &nbsp; &nbsp; Notification</option>
</select>
<div id="Activity">
A
</div>
<div id="Alert">
A
</div>

JavaScript

$("#sel_cat").on('change', function () {
 $( "#sel_cat option:selected" ).html($( "#sel_cat option:selected" ).html().replace(/&nbsp;/g, ''))
});