Answer:
the answer is (a) government stimulation of the economy.
Step-by-step explanation:
All of the other options helped to make the prosperity of the 1920s possible. The rapid expansion of capital, increased productivity of workers, perfection of assembly-line production, and advertising and credit buying all contributed to the economic growth of the 1920s. However, the government did not stimulate the economy during this time. In fact, the government followed a laissez-faire policy, meaning that they did not intervene in the economy, which allowed for the growth of the private sector.