Specialists in marketing have studied how to make people buy more food in asupermarket. They do all kinds of things that you do not even notice. For example, the simple, ordinary food that everybody must buy like bread, milk, flour, and vegetableoil, is spread all over the store. You have to walk by all the more interesting—andmore expensive—things in order to find what you need. The more expensive food isin packages with bright colored pictures. This food is places at eye level so you see itand want to buy it. The things that you have to buy anyway are usually located on ahigher or lower shelf. However, candy and other things that children like are on lowershelves. One study showed that when a supermarket moves four products form floorto eye level, it sold 78 percent more. Another study showed that for every minute a person is in a supermarket afterthe first half hour, she or he spends $50.If someone stays forty minutes, thesupermarket has an additional $5.00.So the store has a comfortable temperature insummer and winter, and it plays soft music. It is a pleasant place for people tostay—and spend more money.Some stores have red or pink lights over the meat so the meat looks redder. They putlight green paper around lettuce（生菜） and put apples in red plastic bags.So be careful in the supermarket. You may go home with a bag of food you were notplanning to buy. The supermarket, not you, decided you should buy itMarketing specialists study _______（）
A. A．plants suitable human needs B.B．how to build shelves C.C．method of selling more products D.D．how to own supermarkets
