Final answer:
The correct option is 2. Industrial
The period between 1900 and 1950 marked the Industrial Age, characterized by a shift towards an industrial economy and known as the era of modern economic growth, resulting from the Industrial Revolution.
Step-by-step explanation:
The stage of economic growth between the years 1900 and 1950 is best described as the Industrial Age. This was a period where there was a significant transition from agrarian economies to industrial-based ones, particularly in Western Europe and North America. The Industrial Revolution had paved the way for this transformation, leading to the phase known as modern economic growth.
During this time, physical capital grew substantially with the expansion of factories and infrastructure, greatly enhancing labor productivity, accelerating economic growth, and shifting the nature of economic activity towards manufacturing and industry. Rapid growth continued from the late nineteenth century onward, leading to a vastly improved standard of living and marked changes in societal structures.