instruction:
Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
question:
Of all the actors who played Doctor Who in the TV series of the same name, who appeared in the most episodes?
answer:
doctor who

question:
Which alliteratively-named politician served as Abraham Lincoln's Vice-President between 1861 and 1865?
answer:
abraham lincoln

question:
Also a three-times World Champion, which American skier won the gold medal in the Women's Downhill at the 2010 Winter Olympics?
answer:
2010 winter olympics