In 1993, New York State ordered stores to charge a deposit on beverage (饮料) containers. Within a year, consumers had returned millions of aluminum cans and glass and plastic bottles. Plenty of companies were eager to accept the aluminum and glass as raw materials for new products, but because few could figure out what to do with the plastic, much of it wound up buried in landfills (垃圾填埋场). The problem was not limited to New York. Unfortunately, there were too few uses for second-hand plastic.

Today, one out of five plastic soda bottles is recycled (回收利用) in the United States. The reason for the change is that now there are dozens of companies across the country buying discarded plastic soda bottles and turning them into fence posts, paint brushes, etc.

As the New York experience shows, recycling involves more than simply separating valuable materials from the rest of the rubbish. A discard remains a discard until somebody figures out how to give it a second life—and until economic arrangements exist to give that second life value. Without adequate markets to absorb materials collected for recycling, throwaways actually depress prices for used materials.

Shrinking landfill space, and rising costs for burying and burning rubbish are forcing local governments to look more closely at recycling. In many areas, the East Coast especially, recycling is already the least expensive waste-management option. For every ton of waste recycled, a city avoids paying for its disposal, which, in parts of New York, amounts to savings of more than $100 per ton. Recycling also stimulates the local economy by creating jobs and trims the pollution control and energy costs of industries that make recycled products by giving them a more refined raw material.

The key problem in dealing with returned plastic beverage containers is ().

A. to sell them at a profitable price

B. how to turn them into useful things

C. how to reduce their recycling costs

D. to lower the prices for used materials