select option rules err

<!--Model-->
function provinsi(){
    $this->db->order_by('name','ASC');
    $provinces= $this->db->get('provinces');
return $provinces->result_array();
}

<!--Controllel-->

    <!--Create-->
    'fakultas'        => $this->model_select->fakultas()

    <!--Rules-->
    $this->form_validation->set_rules('fakultas', 'fakultas', 'trim|required', array('required'   => 'Kolom %s harus di isi!'));

<!--Views-->
<div class="form-group">
                    <label class="control-label col-md-3 col-sm-3 col-xs-12" for="varchar">Fakultas <?php echo form_error('fakultas') ?></label>
                        <div class="col-md-6 col-sm-6 col-xs-12">
                            <select class='form-control' id='fakultas' name="fakultas">
                                <option value='0'>--pilih--</option>
                                    <?php
                                        foreach ($fakultas as $fak) {
                                            echo "<option value='$fak[id]'>$fak[nama_fakultas]</option>";
                                        }
                                    ?>
                            </select>
                        </div>
                    </div>