TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: Which singer played Billie Holiday in the 1972 film `Lady Sings The Blues`?

SOLUTION: lady sings the blues

PROBLEM: Ashgabat is the capital of which country, a former Soviet republic in Asia?

SOLUTION: ashgabat

PROBLEM: In which European city is the famous Arch of Hadrian?

SOLUTION:
arch of hadrian