A、2%. B、3%. C、4%. D、5%. A细节题。从短文中我们可知World population is rising at a rate of two percent a year，选项A是对此的信息重现。

Nowadays, there is a growing awareness of the problem of a rapidly increasing world population. This is largely the result of improved medical skills, which have lowered the death rate and at the same time raised the birth rate by increasing live births and the number of babies who survive early, childhood. There is a growing realization that food production cannot keep pace with these increases, the result of which is that in some countries people are already starving to death while .millions more suffer from lack of nutrition. This problem is further complicated by the fact that in places like America and Europe we obtain by trade and consume far more food and resources like oil than, say, the average Indian, thus leaving even less for the people in the under developed areas to survive on. World population is rising at a rate of two percent a year, and the fastest growing region is Latin America, while Africa closely follows it. However, the largest absolute addition to the world population is in Asia which at present contains about three-fifths of the people of the world.