【正确答案】 B

【答案解析】[听力原文]23-30 It is said that the public and Congressional concern about deceptive packaging rumpus started because Senator Hart discovered that the boxes of cereals consumed by him, Mrs. Hart, and their children were becoming higher and narrower, with a decline of net weight from 12 to 10.5 ounces, without any reduction in price. There were still twelve biscuits, but they had been reduced in size. Later, the senator rightly complained of a store bought pie in a handsomely illustrated box that pictured, in a single slice, almost as many cherries as there were in the whole pie. The manufacturer who increases the unit price of his product by changing his package size to lower the quantity delivered can, without undue hardship, put his product into boxes, bags, and tins that will contain even 4-ounce, 8-ounce, one-pound, two-pound quantities of breakfast foods, cake mixes, etc. A study of drug store and supermarket shelves will convince any observer that all possible size and shapes of boxes, jars, bottles, and tins are in use at the same time and, as the package journals show, week by week, there is never any hesitation in introducing a new size and shape of box or bottle when it aids in product differentiation. The producers of packaged products argue strongly against changing sizes of packages to contain even weights and volumes, but no one in the trade comments unfavourably on the huge costs incurred by endless changes of package sizes, materials, shape, art work, and net weights that are used for improving a product's market position. When a packaging expert explained that he was able to multiply the price of hard sweets by 2.5, from 1 dollar to 2.5 dollars by changing to a fancy jar, or that he had made a 5-ounce bottle look as though it held 8 ounces, he was in effect telling the public that packaging can be a very expensive luxury. It evidently does come high, when an average family pays about 200 dollars a year for bottles, cans, boxes, jars and other containers, most of which can't be used for any thing but stuffing in to the garbage can. 消费者之所以关心包装大小的变化，主要还是因为商品单价也会随之增长。从“The manufacturer who increase the unit price of his prouduct by changing his package size to lower...”可知。