TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: Ashgabat is the capital of which country, a former Soviet republic in Asia?

SOLUTION: ashgabat

PROBLEM: Which two brothers had hits with Cathy's Clown and Wake Up Little Susie?

SOLUTION: cathy's clown

PROBLEM: Formula 1 driver Ayrton Senna died while leading the 1994 San Marino Grand Prix at which motor racing circuit?

SOLUTION:
ayrton senna