What region's population growth and decline history was the demographic transition model originally developed to explain?

The demographic transition model was originally developed to explain the population growth and decline history of Western Europe. This model illustrates the transition from high birth and death rates to lower birth and death rates as a country develops economically. In Western Europe, historical data reflects this transition happening during the industrial revolution, where improvements in healthcare, sanitation, and overall living conditions led to significant changes in population dynamics.

As nations moved from agrarian to industrial economies, urbanization increased, fertility rates began to decline, and life expectancy improved, illustrating the different stages of demographic transition. Western Europe serves as the classic example that has shaped our understanding of population changes over time, making it the correct choice in relation to the demographic transition model.

The other regions mentioned represent varied population patterns and transitions that can differ significantly from the classic model observed in Western Europe, which is why they do not accurately reflect the primary context for the development of this model.