Final answer:
The world’s urban populations are growing at a faster rate than the global population as a whole, especially in developing nations, and this trend is associated with urbanization and economic development. The correct answer is option b.
Step-by-step explanation:
The world's urban populations are growing at a faster rate than the global population as a whole. The number of people living in urban areas has been rapidly increasing and is expected to continue to do so.
The urban population has quadrupled since 1960, while rural populations have grown more slowly. This urban growth is most pronounced in developing nations, where economies are expanding and there is a clear trend of urbanization with an increasing proportion of the population living in cities.
Urbanization presents challenges, especially for less developed countries, as they aim to support growing urban populations sustainably. The movement from rural to urban areas is accompanied by reduced fertility rates and family sizes, which, coupled with the historically larger populations in developing countries, still contribute to overall population growth despite declining growth rates.