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

[EX Q]: What is the title of the four-episode special of 'Doctor Who', made for the Red Nose Day telethon in the UK, broadcast in March 1999?
[EX A]: doctor who

[EX Q]: What is the name of the main thoroughfare in Barcelona, which runs from the Placa de Catalunya to the sea?
[EX A]: barcelona

[EX Q]: Who was the Prime Minister of Canada from 1968 to 1979?
[EX A]:
canada