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

Example Input: Everything Changes, Beautiful World and Circus are all albums released by which British band?
Example Output: beautiful world

Example Input: Who has taken over the TV role of Doctor Who, from actor David Tennant?
Example Output: doctor who

Example Input: Which composer's oratorios include 'The Kingdom' and 'The Dream of Gerontius'?
Example Output:
the dream of gerontius