Final answer:
The rise in gross domestic product in the 1920s was caused by high tariffs that allowed domestic production to expand with little competition.
Step-by-step explanation:
The correct answer is: High tariffs allowed domestic production to expand with little competition. In the 1920s, the U.S. government implemented high tariffs on imported goods, which made foreign products more expensive and less competitive compared to domestic products. This allowed American industries to grow and expand their production without facing significant competition, thus contributing to the rise in gross domestic product (GDP). The protective tariffs gave American businesses an advantage in the domestic market and stimulated economic growth during the 1920s.
Learn more about government policies and the rise in gross domestic product in the 1920s