I don't know what's problem was

This is the return of select2:

and this is my code HTML:

<div class="row">
    <div class="col-sm-12 form-group">
        <label class="form-label-bold">Jenis</label>
        <select class="select2 form-control" id="type" required>
            <option value="">Pilih</option>
            <option value="1">Head Office</option>
            <option value="2">Branch Office</option>
        </select>
    </div>
</div>

and my jQuery:

<script src="https://cdn.jsdelivr.net/npm/select2@4.1.0-rc.0/dist/js/select2.min.js"></script> 
<script type="text/javascript">
$(document).ready(function(){
    $('.select2').select2({})
})
</script>

And this is cdn CSS:

<link href="https://cdn.jsdelivr.net/npm/select2@4.1.0-rc.0/dist/css/select2.min.css" rel="stylesheet" />