TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: In which book of the Bible are the Ten Commandments first mentioned?

SOLUTION: bible

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: Who, in Greek myth, was the daughter of Agamemnon and Clytemnestra, sacrificed at Aulis by her father to ensure a safe passage to Troy?

SOLUTION:
agamemnon