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 input: 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.
Example output: How many books are there in the British Library?
Example 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.
Q: Article: Finally, the long-awaited flying car is almost here. AeroMobil, a Slovakian company, plans to start selling its creation, the AeroMobil3. 0, in 2017. The company claims on its site that the vehicle "transforms in seconds from an automobile to an airplane" by using "existing infrastructure created for automobiles and planes."The vehicle is petrol-powered and has wings that fold, which allows it to be parked like a car, though it is nearly 20 feet long. The company's website features a video where the AeroMobil 3. 0 drives out of a hangar ( )and goes down a highway, sharing the road with ordinary cars until it arrives at an airstrip. The car then unfolds its wings and takes off from a stretch of grass, rather than a paved tarmac , and flies through the air like any other small airplane. AeroMobil spokesman Stefan Vadocz said his company hasn't decided on an exact price because it's not ready yet."The prototype is a work in progress," he said in an email. But he said the price would be several hundreds of thousands of euros---somewhere in between a sports car and a light sports aircraft. The vehicle seats two people---the pilot and a passenger---and its single propeller is located at the rear of the plane. The company said the car's top speed on the road is at least 99 mph and while flying it is at least 124 mph. It can fly for 435 miles before running out of fuel. It has a steel framework and carbon coating and is powered by a Rotax 912, a four-cylinder aircraft engine from BRP of Austria. Flying cars aren't exactly new. The concept has been around since long before The Jetsons popularized the idea in the 1960s. It has been a regular topic in Popular Science ever since World War I ace, Eddie Rickenbacker, wrote about it in 1924. But getting a practical, reliable flying car off the ground has been a serious challenge. Glenn Curtiss discovered this in 1918 when he developed the Curtiss Autoplane. It turned out to be more of a hopper than a flyer, so it failed to become popular with the public.
Answer: Its petrol-powered engine and folding wings.
A:
What allows the AeroMobil3. 0 to be parked as a car?