Doing chores like washing dishes and stacking clothes makes you feel bad? A researcher conducted a survey involving more than 6,000 female volunteers aged 63 to 99. The researchers found that compared with the elderly who were basically immobile Female volunteers who engage in 30-minute chores every day have a 12% lower risk of death. Therefore, researchers believe that simple activities such as housework can help extend life. Which of the following, if true, would most weaken the opinion of the above researchers? ['This study focuses on older women, and those who like sports when they are young can maintain exercise habits as they age.', 'Many seniors can cultivate their own hobbies, such as learning calligraphy, photography, travel, etc. , which will help to prolong the life.', 'There are 554,000 elderly associations in China, with 20 million elderly volunteers, covering most urban and rural communities in the country.', 'The aerobics for the elderly is a set of fitness methods with Chinese characteristics formed by integrating sports, dance, and music into a combination of Chinese and foreign strengths.']