You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
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.

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.
Solution: How many books are there in the British Library?
Why? 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: Article: Tragedy at the Circus In yesterday's circus show, a tiger suddenly attacked its trainer and had to be shot dead. As the circus packed up and left, circus officials said the show would go on, even without tigers. However, the officials cann't simply turn a blind eye to the ethical  problems left behind. Even before this tragedy , animal rights activists protested  against keeping wild animals in unnatural conditions and forcing them to suffer for the profit of circus organizers. It is now time for us to take effective steps to make sure that circus animals are treated properly. ******************************* Circus Safe for Animals Our circus recently suffered a most tragic event in its history. While we are thankful for the pity from the public, we are also astonished by the opinion expressed in "Tragedy at the Circus. " First, our performing animals are not taken from the wild. As to the ethical problems. we always believe humans and animals can--and should--live together nicely. To us, the performing animals are representatives of their species , and our circus is one of the only places left willing to support this special role of performing animals in the existence of the species. Those who argue that circus life is harmful to animals show little knowledge of these facts. Life in the "wild" is unsafe, but a continuous struggle for existence. To overlook these realities is the greatest fault against the animal kingdom. This circus has proven that animals are stronger and smarter than we could imagine. Within the circus is a joyful atmosphere for both animals and humans: people are educated, and species saved. 
 Answer: To call for action to protect circus animals.
Solution:
What is the main purpose of the first passage?