Correct Answer: The North Indian Plains

Solution : The correct option is the North Indian Plains .

The North Indian Plains are one of the most densely populated regions in India. These plains, which include the Indo-Gangetic Plain, are characterised by fertile land and a favourable climate for agriculture. As a result, they have attracted a large population, and cities like Delhi, Patna, and Kanpur are located in this region. The availability of arable land, water resources from rivers like the Ganges and Yamuna, and economic opportunities have contributed to the high population density in the North Indian Plains.