Final answer:
With development, countries increase their consumption of commercial energy sources while subsistence sources are phased out in favor of modern energy solutions.
Step-by-step explanation:
As countries become more developed, their patterns of energy consumption typically change. Economic well-being is often linked with higher energy usage, particularly in the form of commercial energy sources like oil, natural gas, and coal, which power industrial activities, transportation, and many other aspects of modern economies.
In contrast, subsistence energy sources, which include biomass and human or animal power, are more prevalent in less developed regions where they are used for basic needs such as cooking and heating. These are typically phased out in favor of commercial sources as economies grow and modernize.
Moreover, there is a global trend towards renewable energy sources, such as wind, solar, and hydroelectric power. Developed nations are increasingly integrating renewable energy into their mix to reduce dependence on non-renewable resources and address environmental concerns.
Therefore, the correct answer to the question is: A. commercial energy sources increases.