how to create a model object that can handle a single foreign key for people and companies

Question

I am creating an investor object. Investors can be people or companies.

How can I create a model object that could represent either of these types in django?

Here are a few ways I was thinking:

1. Having two non required foreign keys:

     class Investor(models.Model):
     company = models.ForeignKey('companies.Company',on_delete=models.CASCADE, blank=True, null=True)
     customer = models.ForeignKey('accounts.Customer',on_delete=models.CASCADE, blank=True, null=True)
     investor_name = models.CharField(max_length=255)

2. Using a generic relation:

class TaggedItem(models.Model):
    investor_name = models.CharField(max_length=255)
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')

3. An abstract model that is inherited by both customer and company

 class Entity(models.Model)

 class Customer(Entity)

 Class Company(Entity)

What is the most architecturally sound route to go which will not cause me a lot of problems down the line?