TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: Where is the Barbary Coast?

SOLUTION: barbary coast

PROBLEM: Which Chuck Berry song is performed by Marty McFly at the end of the film Back to the Future?

SOLUTION: back to the future

PROBLEM: What is the extramarital dating website whose subscription list was hacked in July 2015?

SOLUTION:
online dating service