Throughout the past 50 years in the United States, there the average gains in lifetime income related along with having a college degree in addition to a high school diploma have: (1) declined since the larger proportion of the population that is college educated has increased dramatically, causing diminishing returns to education to turn into ever stronger. (2) increased markedly, in part because less-skilled American workers face still-increasing competition as the process of globalization proceeds. (3) declined due to increased “outsourcing” of American jobs to well educated foreigners. (4) increased since employers increasingly screen depends solely on educational credentials.
How can I solve my Economics problem? Please suggest me the correct answer.