Dr. Godfrey: Now that high school students are allowed to work more than 15 hours per week at part-time jobs, those who actually do so show less interest in school and get lower grades than those who do not work as many hours at part-time jobs. Obviously, working long hours at part-time jobs during the school year contributes to the academic problems that many of our high school students experience. Dr. Nash: That' s not so. Many of our high school students set out to earn as much money as they can simply to compensate for their lack of academic success. The answer to which one of the following would be the most helpful in determining whether the conclusion that Dr. Godfrey draws could be logically defended against Dr. Nash's counterargument? ['whether people who have had academic problems in high school are ultimately less successful in their careers than people who have not had such problems', 'whether employers and high school students typically obey all the laws that regulate the conditions under which young people may legally be employed', 'whether students are allowed to spend more than 15 hours per week at school-sponsored nonacademic extracurricular activities such as team sports or clubs', 'whether the students who work more than 15 hours per week and have academic problems had such problems before they began to work that many hours']