Open the select but scroll bar appears in window

[xupmtp]

Hi everyone, I use select2 + bootstrap to create my web page

when I open select2, scroll bar will appears

HTML code

<div class="card">
    <div class="col-xl-5">
        <select>
            <option>AAA</option>
            <option>BBB</option>
        </select>
    </div>
</div>

JS code

$('select').select2({})

How can I avoid it, thanks.