Read the article and select the best answer. Article: Over the years, Americans have become used to salt.Most people have no idea how much salt they consume-on average, about 9 to 12 gram per person per day, according to the American Heart Association.That's twice the amount recommended by the government. A new study last week showed eating even a little less salt could greatly help the heart.The scientists said the results would be thirteen percent fewer heart attacks, eight percent fewer strokes , four percent fewer deaths and eleven percent fewer new cases of heart disease. Researchers also found that the benefits would be greatest for African Americans and women.As a group, African Americans tend to have higher blood pressure than the general population, and "many studies suggest that they may be more sensitive to salt," says Dr.Kirsten Bibbins-Domingo, an epidemiologist at the University of California, San Francisco.Her analysis found that a reduction of 3 gram of salt per day would reduce heart attacks 8% on average; among African Americans, that rate would drop 10%.A similar result was found in women, whose stroke risk dropped 8% with a 3-g reduction in salt intake; in men, the risk fell 5%. They and public health professionals in the United States are interested in a national campaign to persuade people to eat less salt. However, other scientists say such a campaign is an experiment with the health of millions of people. Michael Alderman, a high blood pressure expert and professor at Albert Einstein College of Medicine in New York, says that eating less salt results in lower blood pressure.But he says studies have not clearly shown that lowering salt means fewer heart attacks or strokes. "Salt has other biological effects. Calling for reductions in the national diet could have good effects, as well as harmful results. There is not enough evidence either way,"said Michael Alderman. Question: The author's attitude toward the study is _ . Options: A: cold B: objective C: subjective D: doubtful
B