Based on studies by the state health department, the Surgeon General has formulated tables that list standard exercise requirements for various age groups. People whose activity level falls within the range given for their age experience fewer cardiovascular problems than those whose activity level falls below the given range. Ttherefore, if people whose activity level falls below their given range increased their time exercising to fall within that range, their cardiovascular health would improve. Which one of the following is an assumption on which the argument relies? ['The Surgeon General intended her table to help motivate people to increase their activity level and improve their cardiovascular health.', "People who follow the Surgeon General's table guidelines have better overall health than those who do not.", 'Increasing the activity level would not itself cause cardiovascular health problems for people.', 'Some individuals would be willing to increase their activity level solely to improve their cardiovascular health.']