PHP Form Drop Down menu stills blanck after I select an item

I am executing an form based on PHP on Windows, however after I select an item in the drop down menu, the text does not show up (even though it was selected properly, as I can verify in the database after clicking the insert button).

The form code:

            <form action="inserir_transportadoras.php" method="post">
                <input type="text" name="nometransportadora" placeholder="Nome da Transportadora">
                <input type="text" name="endereco" placeholder="Endereço">
                <input type="text" name="telefone" placeholder="Telefone">
                <input type="text" name="cidade" placeholder="Cidade">
                <select name="estados">
                    <?php
                        while($linha = mysqli_fetch_assoc($lista_estados)) {
                    ?>
                        <option value="<?php echo $linha["estadoID"];  ?>">
                            <?php echo utf8_encode($linha["nome"]);  ?>
                        </option>
                    <?php
                        }
                    ?>                        
                </select>
                <input type="text" name="cep" placeholder="CEP">
                <input type="text" name="cnpj" placeholder="CNPJ">
                <input type="submit" value="inserir">
            </form>
        </div>

The dropdown menu PHP code:

<input type="text" name="cidade" placeholder="Cidade">
                    <select name="estados">
                        <?php
                            while($linha = mysqli_fetch_assoc($lista_estados)) {
                        ?>
                            <option value="<?php echo $linha["estadoID"];  ?>">
                                <?php echo utf8_encode($linha["nome"]);  ?>
                            </option>
                        <?php
                            }
                        ?>                        
                    </select>

How can I solve it?