Researchers analyzed the results of telephone interviews and laboratory tests of 990 people aged 40 to 70 and found that optimists are less likely to have high "bad" cholesterol (that is, low-density lipoprotein) and "good" cholesterol (High-density lipoprotein) is higher, which has a protective effect on the heart and helps offset "bad" cholesterol. Therefore, research believes that this is another evidence that mental health is closely related to physical health, and optimistic temperament may be beneficial to human health There are some real benefits. Which of the following, if true, would best support the above findings? ['the study has not yet found a link between optimism and total cholesterol levels.', 'optimists have a healthier lifestyle, which makes their blood lipids different from other people.', 'there are a large number of sports enthusiasts interviewed, and regular exercise can reduce their risk of heart disease.', 'In the experiment, every 5 points increase in optimism score increases 1 mg per 100 ml of HDL, which means that the risk of heart disease is reduced by 3%.']