Which of the following river basins is most densely populated?

The Ganges river basin is the most densely populated among the four river basins listed. The Ganges river basin is home to more than 400 million people who rely on the river for their livelihoods and survival. The basin includes parts of India, Nepal, and Bangladesh, which are some of the most populous countries in the world. The Ganges river is also considered a holy river by many Hindus, which has led to the development of many cities and towns along its banks, further contributing to the high population density in the area. In summary, the Ganges river basin is the most densely populated due to a combination of factors such as the high population of the countries it flows through, its importance to people's livelihoods, and religious significance.