Though dry regions may never be as densely populated as those near water, which of the following has led to increased populations in dry areas?

Dry areas were never as crowded as those areas near the waters however, the development of better technologies that allow access to more water supplies has caused the increased population in dry areas. Water is made readily accessible to remote and dry areas due to current developments in science.

Here is a picture  of the net. its 4 squares in a row diagonal and on the third draw one square aove and under

I’m guessing probably a