Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

What country has an official residence called Blair House, kept for guests of the leader of the country?
blair

Which Renaissance artist's life was fictionalised in the book 'The Agony and the Ecstasy' subsequently made into a film?
the agony and the ecstasy

What country is found on Bulgaria's northern border?

bulgaria