public function selectFull()
 {
     $sql = "select * from resposta_multipla";
     $result = $this->retrieve($sql);
     $lista = array();
     while ($qr = mysqli_fetch_array($result)) {
         $rem = new RespostaMultipla();
         $rem->setRspm_id($qr["rspm_id"]);
         $rem->setRspm_usuario($qr["rspm_usuario"]);
         $rem->setRspm_exercicio($qr["rspm_exercicio"]);
         $rem->setRspm_questao($qr["rspm_questao"]);
         $rem->setRspm_resposta($qr["rspm_resposta"]);
         array_push($lista, $rem);
     }
     return $lista;
 }