Referential integrity violations

Given the current state of your database, what happens if you execute the following SQL statement?

DELETE FROM universities WHERE id = 'EPF';

Möjliga svar

It throws an error because the university with ID "EPF" does not exist.

The university with ID "EPF" is deleted.

It fails because referential integrity from universities to professors is violated.

It fails because referential integrity from professors to universities is violated.