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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: Sports can help you keep fit and get in touch with nature.However,whether you are on the mountains,in the waves,or on the grassland,you should be aware that your sport of choice might have great influence on the environment. Some sports are resource-hungry.Golf,as you may know,eats up not only large areas of countryside,but also tons of water.Besides,all sorts of chemicals and huge amounts of energy are used to keep its courses in good condition.This causes major environmental effects.For example,in the dry regions of Portugal and Spain,golf is often held responsible for serious water shortage in some local areas. There are many environment-friendly sports.Power walking is one of them that you could take up today.You don't need any special equipment except a good pair of shoes;and you don't have to worry about resources and your purse.Simple and free,power walking can also keep you fit.If you walk regularly,it will be good for your heart and bones.Experts say that 20 minutes of power walking daily can make you feel less anxious,sleep well and have better weight control. Whatever sport you take up,you can make it greener by using environment-friendly equipment and buying products made from recycled materials.But the final goal should be"green gyms".They RYe better replacements for traditional health clubs and modern sports centers. Members of green gyms play sports outdoors,in the countryside or other open spaces.There is no special requirement for you to start your membership.And best of all,it's free. 
 Answer: Cycling around a lake.
Solution:
Which of the following is the author most probably in favor of?