How to use Radio Field with EntityType Symfony 3

Demande.php

<?php
namespace DemandeBundle\Form;

class  DemandeType extends AbstractType {
   /** @var EntityManagerInterface $em */
    private $em;

    /**
     * 
     * @param EntityManagerInterface $em
     */
    public function __construct(EntityManagerInterface $em) {
        $this->em = $em;
    }

    /**
     * @param FormBuilderInterface $builder
     * @param array $options
     */
    public function buildForm(FormBuilderInterface $builder, array $options) { 
  
      $builder
          ->add('typedecision', EntityType::class, array(
                    'label' => 'Type of support',
                    'label_attr' => array(
                        'for' => 'demandes_demande_type_decision',
                        'class' => 'radio-inline'
                    ),
                    'attr' => array(
                    ),
                    'required' => false,
                    'read_only' => false,
                    'class' => 'DemandesBundle:Decision',
                    'query_builder' => function (EntityRepository $er) {
                        return $er->createQueryBuilder('u')
                                ->orderBy('u.libelle', 'ASC');
                    },
                   
                    'expanded' => true,
                    'property' => 'libelle',
                ));
    }
       /**
     * {@inheritdoc}
     * @param OptionsResolver $resolver
     */
    public function configureOptions(OptionsResolver $resolver) {
        $resolver->setDefaults(array(
            'data_class' => 'DemandesBundle\Entity\Demande'
        ));
    }

    /**
     * {@inheritdoc}
     * @return string
     */
    public function getName() {
        return "demandes_obj_demande_form";
    }
}