JSFiddle - React, Tailwind, and code Playground

HTML

<select name="aa">
    <option>a</option>
    <option>b</option>
    <option>c</option>
</select>

<select name="ab">

</select>

JavaScript

var src = $("select[name='aa'] option:eq(0)");

var tar = $("select[name='aa']")
    
tar.append(src.clone())