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

In May 1940, who became British Prime Minister after the resignation of Neville Chamberlain?
prime minister of the united kingdom

Devil's Tower National Monument in Wyoming, USA features prominently in which landmark 1977 science fiction film?
devils tower

Name the landlocked country which has borders with Kosovo, Serbia, Bulgaria, Greece and Albania.?

greece