如何在Symfony3表单中设置默认国家/地区？

I'm using Symfony3 form. I have aCountryType in my Symfony form Builder. It's working correctly. But suppose the user belongs to a Company which is based in Spain. For that User I want to set the default country to be Spain and then show the rest of the countries. How can I do this in Symfony3.

I tried this but its not working.

        $builder->add("country", CountryType::class, array(
        "label" => "Country",
        "required" => false,
        "preferred_choices" => array(
            "ES" => "Spain",
        ),
    ));

Thank you for your time.

In this type Country::class, for use the preferred selection on array you should use:

->add('country', CountryType::class, [
    'preferred_choices' => ['DE'],
    'label' => 'address.form.country.label',
    'attr' => [
        'class' => 'form-control',
        'placeholder' => 'address.form.country.placeholder'
    ],
    'label_attr' => [
        'class' => 'col-sm-2 col-form-label'
    ],
])