In terms of demographics, which country is likely to experience the greatest population growth problem over the next ten years?

A) Mexico, because there are fewer pre-reproductive individuals in their population B) China, whose population is more than a billion, but whose expected fertility rate is 1.8 children C) Germany, where the growth rate of the population is 0.1% per year D) United States (2009 population ~ 205,000,000, where 200,000 Americans are added to the population each day) E) Afghanistan, with a 3.85 annual growth rate