TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: Who is the only British Prime Minister to serve under 3 monarchs?

SOLUTION: prime minister of the united kingdom

PROBLEM: In which constellation is the star Deneb?

SOLUTION: deneb

PROBLEM: Clint Eastwood played the character of Rowdy Yates in which US TV series of the 1960s?

SOLUTION:
clint eastwood