单选题：One of the greatest killers in the Western world is heart di

One of the greatest killers in the Western world is heart disease. The death rate (率) from thedisease has been increasing at an alarming speed for the past thirty years. Medical experts know thatpeople can reduce their chances of getting heart disease by exercising regularly, by not smoking, bychanging their diets ,and by paying more attention to reducing stress( 压力)in their work.
However, Western health-care systems are still not paying enough attention to the prevention ofthe disease. There is a need for more programs to educate the public about the causes and preventionof heart disease. Instead of supporting such programs, however,the U. S. health-care system is spend-ing large sums of money on the surgical( 外科的)treatment of the disease after it develops. This em-phasis(强调) on treatment clearly has something to do with the technological advances that havetaken in the past ten to fifteen years. In this time, modern technology has enabled doctors to developnew surgical techniques. Many operation that were considered impossible or too risky (有风险的) afew years ago are now performed every day in U. S. hospitals. The result has been a huge increase inheart surgery.
Although there is no doubt that heart surgery can help a large number of people, some peoplepoint out that the emphasis on the surgical treatment of the disease has three clear disadvantages.
First, it attracts interest and money away from the question of prevention. Second, it causes the costsof general hospital care to rise. After hospitals buy the expensive equipment that is necessary formodern heart surgery, they must try to recover the money they have spent. To do this, they raise costsfor all their patients, not just those patients whose treatment requires the equipment. The third disad-vantage is that doctors are encouraged to perform surgery--even on patients for whom an operation isunnecessary--because the equipment and expert skills are there. A govermnent official recentlystated that major heart surgery was often performed even though its chances of success were low. Inone type of heart surgery, for example, only 15 percent of patients improved their conditions after thesurgery. However,more than 100,000 of these operations are performed in the United States everyyear.
根据以上内容,回答题.
（　） What effect has modern technology had on medicine? A．It has reduced the costs of medical treatment.
B．It has helped save the lives of most patients.
C．It has encouraged doctors to do more heart surgeries.
D．It have helped educate people about the prevention of heart disease.