Given the task definition, example input & output, solve the new input case.
In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.
Example: Article: There are a lot of public libraries in Britain. These libraries have more than one hundred and fifteen million books, not including those libraries of public schools. Public libraries not only lend books, music records but also help children, patients in hospitals and others to get special play readings, film shows and so on. The first public libraries were founded in about the year 1850. Today's public libraries usually have a reading-room, a lending room and a reference room. The greatest and most famous library in Britain is that of the British Library in London. It was founded in 1973 and has over 10, 000, 000 books. It has nearly every magazine, newspaper and book published in Britain and other parts across the world.
Answer: 10,000,000 or less.
Output: How many books are there in the British Library?
In the Article, 10,000,000 is mentioned for the number of books available in the British Library, so this is a good question.

New input case for you: Article: The largest campaign of killing rats in history is set to poison millions of rats on the sub-Antarctic island of South Georgia. Scientists say the campaign planned for 2013 and 2014 will restore beautiful South Georgia to the position it once held as the world's most important nesting sites for seabirds. It was sailors in the late 18th century who unintentionally introduced rats to what had been a fresh environment. "If we can destroy the rats, at least 100 million birds will return to their home on South Georgia," says Tony Martin, a biology professor at the University of Dundee who was invited to lead the project. South Georgia is by far the largest island to get rid of animals that destroy native wildlife after being introduced deliberately or accidentally by people. Though rats and mice have done the most damage, cats, foxes, goats, deer, rabbits and other species have been targeted in the campaigns around the world. South Georgia is seven times the size of New Zealand's Campbell Island, currently the largest area ever killing rats. The successful war against Campbell Island rats was carried out in 2001 with 132 tons of poison dropped from five helicopters. "New Zealand pioneered the techniques for ridding islands of rats and in fact our operation on South Georgia is based on New Zealand's technology." Says Martin. "Some New Zealanders will be helping our campaign, including our chief pilot, Peter Garden, who was also chief pilot for the projects at Campbell Island and Rat Island, in the Aleutian chain of the north Pacific." The second and third stages in 2013 and 2014 will involve dropping as much as 300 tons of poison from the air onto every part of the island where rats might live. It is a huge operation, carried out during the stormy southern autumn when the rats are hungry and the risks of poisoning native wildlife are less than in the spring and summer months. "Ideally we'd do in winter but the weather makes that too risky," Martin says. The ecological payback will be priceless. But Martin says, "The full benefits will take decades to arrive, because some of these birds are slow to hatch."
Answer: They were brought in by people deliberately.
Output:
According to the passage, how did the rats appear on the sub-Antarctic island of South Georgia?