The Ganges is a trans-boundary river of Asia which flows through the nations of India and Bangladesh, roughly "40%" of the Indian population that lives in the lower and middle Ganges river basin, although this figure changes slightly depending on the exact time in question.
Approximately 40% of the Indian population resides in the lower and middle Ganges River basin. This is due to the area's fertile land, economic opportunities, and historical significance. Therefore, the correct answer is D. 40%.
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