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: Shopping is not as simple as you think! There are all sorts of tricks at play each time we reach out for that particular brand of product on the shelf. Coloring, for example, varies according to what the producers are trying to sell. Health foods are packages in greens, yellows or browns because we think of these as healthy colors. Ice cream packets are often blue and expensive foods, like chocolates, are gold and silver. When some kind of pain killer was brought out recently, researchers found that _ because they made the product look weak and ineffective. Eventually, it came on the market in a dark blue and white package because we think of it as safe, and white as calm. The size of a product can attract a shopper. But quite often a bottle doesn't contain as much as it appears to. It is believed that the better-known companies spend, on average, 70 percent of the total cost of the product itself on packaging. The most successful producers know that it's not enough to have a good product. The founder of Pears soap, who for 25 years has used pretty little girls to promote their goods, came to the conclusion: "Any fool can make soap, but it takes a genius to sell it."
Answer: The brand name of the product.
Solution:
Which of the following may trick a shopper into buying a product according to the text?