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

Example Input: What is the name of the US electric car manufacturer, founded in 2003, whose cars include the Model S and the Model X?
Example Output: tesla model s

Example Input: 'Arthur Clennam', 'Jeremiah Flintwinch', and 'Edward Sparkler' are all characters in which Dickens' novel?
Example Output: arthur clennam

Example Input: The group Smile, formed in 1968 by Roger Taylor, Tim Staffel and Brian May, changed their name to what after Tim Staffel was replaced as vocalist?
Example Output:
brian may