【单选题】

Store shelves are filling up with so-called "green" products promising to benefit the environment.

A、recent controversy pitting the influential magazineConsume Reports against a popular new energy-saving device shows that it can be as difficult for buyers to confirm such claims as for manufacturers to defend them.
The controversy concerns the GreenPlugElectricity Saver ($29～$39 retail).Consumers snapped 500 000 in 1993, the plug’s first year on the market. Gross revenue was $10 million for the fledgling manufacturer, Green Technologies InC、, ofBoulder,Colo.
The GreenPlug is supposed to prevent energy waste by appliances whose constant-speed motors operate at less than full load—as is especially true of older refrigerators. Research conducted for the space shuttle showed that such motors can be made to do the same work with less heat, noise, and power consumption just by lowering the voltage of the power supply.
John and Wyck Hay, two of the founders of theCelestial Seasonings Herb TeaCompany, started Green Technologies in 1990 to apply that finding to home appliances. In the United States alone, there are more than 140 million refrigerators in use, accounting for an average of 16 percent of the household electric bill. That share can run as high as 25 percent in a small apartment.
Two years of research resulted in the GreenPlug.Connecting between wall socket and refrigerator, the device contains an analog computer that gives a motor full power (120 V on average) for start-up, then reduces the power to 106 V.
That boosts the efficiency, but a lot of factors affect how much electricity and money are saveD、Line voltage varies from home to home.
Older refrigerators are the most overpowered and, thus, save the most energy with a GreenPlug. Refrigerators less than two years old are so efficient already that a GreenPlug actually makes them waste electricity.
The higher the voltage, the larger the difference a GreenPlug makes.
Higher power costs shorten the payback time. The population-weighted national average is 10 cents per kilowatt-hour.But some residents in Washington State pay 1.5 cents. Some inAlaska pay 416 cents.
Then come highly individual household factors like the number of children of refrigerator-opening age.All in all, the GreenPlug should save the average consumer $20 a year, says SteveEhli, director of public relations for Green Technologies.
Controversy over the GreenPlug began whenBernardDeitrick, a project leader atConsumers Union, tested the device on refrigerators made in 1969, 1975, 1978 and 1992. His results appeared in an unfavorable review in the November issue ofConsume Reports, drawing a barrage of challenges from Green Technologies as well as Green-Plug vendors and customers.
Although the GreenPlug lowered the voyage as it was designed to do,Consume Reports questioned how quickly—if ever—electricity savings attributable to the plug would repay its cost. People would be better of buying a new, high-efficiency refrigerator, the magazine adviseD、..
Consumer Reports also said that the GreenPlug didn’t give a claimed 25 percent savings worth $50 a year. The savings on the oldest model was the best at 8.6 percent, worth $20 a year.
Green Technologies responded that by November it had discontinued a pamphlet that implied that the GreenPlug could deliver a 25-percent savings.And it had never used the $50 figure.
Green Technologies ordered tests of the GreenPlug on up to 2800 refrigerators through next year. Mr.Ehli says the company will not put that data in stores. Instead, potential buyers will call an 800 numbers to learn how their model of refrigerator performeD、
Meanwhile, there is little evidence of consumer dissatisfaction. Sales topped 45000 units last month. The return rate is less than 0.2 percent,Ehli says.
The electrical saving provided by the G