单选题：根据下列材料，请回答题In the United States alone, over 100 million cell

根据下列材料，请回答题
In the United States alone, over 100 million cell-phones are thrown away each year. Cell-phones are part of a growing mountain of electronic waste like computers and personal digital assistants. The electronic waste stream is increasing three times faster than traditional garbage as a whole.
Electronic devices contain valuable metals such as gold and silver. A Swiss study reported that while the weight of electronic goods represented by precious metals was relatively small in comparison to total waste, the concentration (含量) of gold and other precious metals was higher in So-called e-waste than in naturally occurring minerals.
Electronic wastes also contain many poisonous metals. Even when the machines are recycled and the harmful metals removed, the recycling process often is carried out in poor countries, in practically uncontrolled ways which allow many poisonous substances to escape into the environment.
Creating products out of raw materials creates much more waste material, up to 100 times more, than the material contained in the finished products. Consider again the cell-phone, and imagine the mines that produced those metals, the factories needed to make the box and packaging(包装) it came in. Many wastes produced in the producing process are harmful as well.
The U.S. Environmental Protection Agency notes that most waste is dangerous in that “the production, distribution, and use of products — as well as management of the resulting waste — all result in greenhouse gas release.” Individuals can reduce their contribution by creating less waste at the start — for instance, buying reusable products and recycling.
In many countries the concept of extended producer responsibility is being considered or has been put in place as an incentive (动机) for reducing waste. If producers are required to take back packaging they use to sell their products, would they reduce the packaging in the first place?
Governments’ incentive to require producers to take responsibility for the packaging they produce is usually based on money. Why, they ask, should cities or towns be responsible for paying to deal with the bubble wrap (气泡垫) that encased your television?
From the governments’ point of view, a primary goal of laws requiring extended producer responsibility is to transfer both the costs and the physical responsibility of waste management from the government and tax-payers back to the producers.
By mentioning the Swiss study, the author intends to tell us that _________ . A．the weight of e-goods is rather small
B．E-waste deserves to be made good use of
C．natural minerals contain more precious metals
D．the percentage of precious metals is heavy in e-waste