TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: Which biologist was known as Darwin's Bulldog?

SOLUTION: charles darwin

PROBLEM: Betty Driver played which role in Coronation Street?

SOLUTION: betty driver

PROBLEM: Which British sitcom about the Home Guard in World War II was written by Jimmy Perry and David Croft and broadcast between 1968 and 1977, running for 80 episodes?

SOLUTION:
david croft