Final answer:
The world's most populous countries are predominantly located in East Asia, a region that includes China, the world's most populous country, as well as other densely populated nations. Option a. east asia is the correct answer.
Step-by-step explanation:
Some of the world’s most populous countries are located in East Asia. This region includes countries like China, which is the world's most populous country, and other densely populated nations such as Japan and South Korea. Population distribution on a global scale shows clusters in specific regions, and East Asia is one of the three largest population clusters. The other two major population clusters are in South Asia, which includes India, and Europe.
Additional significant population centers are found in regions with high urbanization, such as the northeastern United States' megalopolis area, as well as in the tropics like Nigeria in West Africa and Java in Indonesia.
These areas are notable for their large, concentrated populations, which are a result of various factors including history, economy, and geography. Large populations can lead to dynamic economic activity but also present challenges such as resource management and sustainable development.
Therefore, the correct answer to the question is 'a. East Asia.'