instruction:
Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
question:
Which horse won the 2008 Grand National?
answer:
2008 grand national


question:
Which model was married to photographer David Bailey for 10 years, from 1975?
answer:
david bailey


question:
In April 2004, which player scored the winning goal for Chelsea to knock Arsenal out of the Champions League?
answer:

chelsea f.c.