Final answer:
Asia is the continent with the most Indian and Chinese populations, as it houses the world's two most populous countries, China and India.
Step-by-step explanation:
The continent that has the vast majority of the Indian and Chinese population is Asia. Asia leads the world in population size, with China and India being the two most populous countries globally, each having a population of over a billion people. Historically and presently, Asia has represented a center of world population, with its history as old as or even older than Western history. Considering contemporary population growth, much of it is occurring in Asia, with additional significant increases in countries like Pakistan and regions like Africa, which have high fertility rates.
Therefore, the correct answer to the question is A) Asia.