If two countries have the same fertility rate but country A has higher life expectancy, which difference is more likely in the long run?

Correct answer: Country A may have a higher proportion of elderly people

The governing concept is that age structure depends on fertility, mortality, survival and migration, not on fertility alone. When country A has higher life expectancy, a larger fraction of its population is likely to survive into older age groups. Over time, this can raise the proportion of elderly people, even though the fertility rates of the two countries are identical. Option A is therefore the most reasonable conclusion. Option C is incorrect because equal fertility does not guarantee equal mortality or survival patterns. Option B contradicts the meaning of higher life expectancy, while option D is impossible because a population contains several age groups. The result is a likely tendency, not an absolute prediction, since migration and other demographic conditions may also influence the final structure.