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

What is the country of origin of the cheese called caerphilly?
caerphilly cheese

Who bad a number 1 in the 1980's with Circle in the Sand?
circle in the sand

In Greece, what is a dish that is mainly cucumber mixed with garlic and yoghurt called?

garlic