user: Detailed Instructions: 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.
See one example below:
Problem: 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?
Explanation: In the Article, 10,000,000 is mentioned for the number of books available in the British Library, so this is a good question.

Problem: Article: The energy crisis has made people aware of how the careless use of the earth's energy has brought the whole world to the edge of disaster. The over-development of motor transport, with its increase of more cars, more traveling, has contributed to the near-destruction of our cities and the pollution not only of local air but also of the earth's atmosphere. Our present situation is unlike natural disasters of the past. Worldwide energy use has brought us to a state where long-range planning is vital. What we need is not a continuation of our present serious state, which endangers the future of our country, our children, and our earth, but a movement forward in order to work rapidly and effectively on planetary problems. This country has been failing back under the continuing exposures of loss of morality and the revelation  that lawbreaking has reached into the highest place in the land. There is a strong demand for morality to turn for the better and for some devotion that is vast enough and yet personal enough to enlist the devotion of all. In the past it has been only in a way in defense of their own country and their own benefits that people have been able to devote themselves wholeheartedly. This is the first time that we have been asked to defend ourselves and what we hold dear in cooperation with all the other people of this planet, who share with us the same endangered air and the same endangered oceans. There is a common need to reassess our present course, to change that course and to employ new methods through which the world can survive. This is a priceless opportunity. To grasp it, we need a widespread understanding of nature if the crisis we and the world are facing is no passing inconvenience, no byproduct of the ambitions of the oil-producing countries, no environmentalists' only fears, no byproduct of any present system of government. What we face is the result of the invention of the last four hundred years. What we need is a transformed life style. This new life style can flow directly from science and technology, but its acceptance depends on a sincere devotion to finding a higher quality of life for the world's children and future generation. 
 Answer: The rapid growth of motors.
Solution:

assistant: Which of the following has nearly destroyed our cities?