单选题
Convincing the public to follow health advice can be tough and time-consuming. This may be why changes to health messages are often fiercely resisted by those whose job is to get the advice across. So, for example, the suggestion that smokers who cannot quit should reduce their exposure to harm by switching to chewing tobacco met with extreme opposition. A still more ferocious debate is emerging over the health impact of sunshine. For the past 20 years, advice on sunlight has come from dermatologists who rightly warn people to cover up when they venture outside for fear of developing skin cancer. But evidence from researchers in other fields now suggests that short periods in the sun without protection—sometimes as little as a few minutes a day—can prevent most other major forms of cancer. This surprising conclusion stems from findings that vitamin D, which is made by skin cells exposed to the sun" s ultraviolet rays, is a potent anti-cancer agent. The researchers who made this discovery are eager to be heard. But their message is about as welcome as a bad rash, particularly in countries such as Australia and the US where fair-skinned immigrants living at Mediterranean latitudes have made skin cancer a huge problem. The American Academy of Dermatology argues that advocating one carcinogen—UV radiation—to protect against other forms of cancer is dangerous and misleading. If people need more vitamin D, they should take a multivitamin or drink milk fortified with it, says the academy. Unfortunately , the solution is not as simple as that. Critics also argue that the protective effect of sunlight is not yet proved. While this may be true, the evidence is very suggestive. The case is built on several studies that bring together cellular biology, biochemistry and epidemiology. And all the criticism of this theory counts for nothing if, as some of its advocates, suggest, the number of people dying for lack of sunlight is four times as high as those dying from skin cancer. At the same time, those advocates must not overstate their case. Everyone wants to save as many lives as they can. What we need now is for national medical research bodies and cancer research organizations to investigate the relative risks and benefits of sunshine. This will almost certainly mean more epidemiological work, which should start as soon as possible. As for the public: give them the facts, including risk estimates for short periods in the sun—and for covering up, It is patronizing(施恩于人的)to assume that people cannot deal with complex messages. What we definitely do not want is a war of words between groups with polarized views, and no prospect of the issue being resolved. That way will only lead to confusion, distrust of doctors and more unnecessary deaths.
单选题
According to the first two paragraphs, the problem seems to be that the public______.