Among the countries on the margins of the South Asian region, population growth is highest in A. the Maldives. B. Nepal. C. Sri Lanka. D. Afghanistan.

D is the correct answer. According to the 2010 - 2015 list of population growth by the United Nations, Afghanistan is number 21 on the list. This is followed by the Maldives at number 76, then Nepal at number 120, and finally Sri Lanka at number 160.