Easy access to safe drinking water is the correct statement.
Option (d);
EXPLANATION:
Carrying capacity means the maximum number of species that can live in one given area without the resources getting depleted. If a country has a high carrying capacity it means they would easily access safe drinking water.
It will also include other resources like food and raw materials available easily in such parts of the world. Water is essential for one's survival, an area that has high carrying capacity is directly related to easy access of safe drinking water.