Which of these rivers is the southernmost in China? Xi Jiang
Huang He
Chang Jiang
Yalu Jiang

Cpopulation density

The correct answer is a)  a resource with a limited supply; it will run out.

If a particular resource is not useful or needed then the price would be considerably low. once that resource is needed the price or value will raise depending on how useful or needed it is especially if the resource is low in quantity, the consumers would pay whatever they have to, to get that material.