Why some regions are more extremely affected by water scarcity than others?

Water scarcity can mean scarcity in availability due to physical shortage, or scarcity in access due to the failure of institutions to ensure a regular supply or due to a lack of adequate infrastructure.

Water scarcity already affects every continent. Water use has been growing globally at more than twice the rate of population increase in the last century, and an increasing number of regions are reaching the limit at which water services can be sustainably delivered, especially in arid regions.

the answer is the last option or letter d)

heat from the core of the earth causes convection currents to occur in the mantle. these currents slowly move the crust around.