Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

Ex Input:
On which holiday island are the peaks of 'Ruivo' and 'Arieiro', and the airport of 'Santa Cruz'?

Ex Output:
pico do arieiro

Ex Input:
Chris Martin is the lead singer with which band who had several hits in the 2000s?

Ex Output:
chris martin

Ex Input:
Who wrote the music for what he described as an American folk opera, which was set on Catfish Row?

Ex Output:
catfish row