The one variable that stands out as the most significant explanation of large variations in living standards around the world is a. productivity. b. population. c. preferences. d. prices.

The answer is (D) productivity.

Explanation:

Each country manages to generate products and operate businesses at a different rate from one another. Those who are able to do more - whether in quality and quantity - tend to do better in living standards than countries that do less. Though this might be occurring in a micro-economic level, the productivity generated by its citizens through these efforts would impact the country on a macro-level; from strengthening the country's currency to reducing the overall unemployment rate.