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 alliteratively-named politician served as Abraham Lincoln's Vice-President between 1861 and 1865?

SOLUTION: abraham lincoln

PROBLEM: Thereze Bazar and David van Day were better known as which duo?

SOLUTION: david van day

PROBLEM: Who wrote the book from which Sir Benjamin Britten created the opera 'Billy Budd'?

SOLUTION:
billy budd