Class selectpicker Bootstrap, does not recognize option insertion via jquery (.html ())

I'm using Bootstrap framework, and the Selectpicker class to get the city data as state. The script works fine, it returns data, but instead of entering <option> Cidade X </option> it only inserts Cidade X . I know the problem is in the class, but I do not know how to solve it. Class:

<div class="col-md-3  col-xs-4" id="cidade">

<select data-width="auto" id="municipio" name="municipio" class="selectpicker municipio">
    <option value="0" disabled="disabled">Selecione o estado</option>
</select>
</div>

Script:

    $(document).ready(function(){

    $("#estado").change(function() {

        var est = document.getElementById("estado").value; 

        debugger;

        $.ajax({
        type: 'post',
         url: 'cidade.php',
         data: {
          cd_estado: est
         },
         success: function(dados) {
            $(".municipio").html(dados);
         }
         });

    });
});