How to display a Foreign key serializer as a dropdown?

I have three different models:

class Province(Model):
    province = models.CharField(max_length=250)

class BaseCase(ModelWithStamps):
    ...
    province = models.ForeignKey(Province, null=True, blank=True, on_delete=models.CASCADE)

class Event(BaseEvent):
   ....
    @property
    def province(self):
        if hasattr(self, 'case'):
            return self.case.province
        return None

    @property
    def province_id(self):
        if hasattr(self, 'case'):
            return self.case.province.id
        return None

And I have a serializer:

class BaseEditCaseSerializer(...):
    ....
    province = serializers.ModelField(model_field=Case()._meta.get_field('province'),
                                      required=False, allow_null=True)

    class Meta:
        model = ManualEvent
        fields = (..., 'province')

Even, the province is a foreign key, the province field is displayed as a "text field" in front end and I cannot change it from there.

I want to display it as a dropdown (Province.objects.all()). How can I do it?

from How to display a Foreign key serializer as a dropdown?