Final answer:
East Asia is home to some of the world's most populous countries, including China. While West Africa, particularly Nigeria, has a significant population, it does not rival the size of East Asia's population clusters. Economic size and population growth are most pronounced in developing regions of Asia and Africa.
Step-by-step explanation:
The answer to the question "Some of the world’s most populous countries are located in which region?" is a) East Asia. This region includes countries like China, which is the most populous country in the world, and others in the surrounding area. Other populous regions mentioned include South Asia, with India and Pakistan experiencing significant population growth, and Europe, which also hosts large population clusters despite having a stable or declining population in some areas. It's worth noting that while West Africa, particularly Nigeria, has a burgeoning population, it does not compare to the immense population clusters in East Asia.
In terms of economic size on a GDP basis, East Asia is one of the largest economies; however, when considering GDP per capita, it falls behind Europe and Central Asia. Furthermore, regions such as Southeast Asia, and specific populous countries like Nigeria and Indonesia with the island of Java, are notable for their significant population clusters. Population growth tends to be more pronounced in developing countries, particularly in Asia and Africa.