TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: What is the name of the main thoroughfare in Barcelona, which runs from the Placa de Catalunya to the sea?

SOLUTION: barcelona

PROBLEM: Richard Block and David Quayle founded which British-based DIY retailing company in 1969?

SOLUTION: david quayle

PROBLEM: Christopher Reeve had the title role in the first of which series of films?

SOLUTION:
christopher reeve