The factor that did not contribute to the rapid population growth in the United States in the early 1900s is:
More people moved from farms to large cities.
While urbanization was occurring, it is not a direct factor that contributed to population growth itself; rather, it reflects a shift in where people lived. The other factors—higher immigration rates, a higher birth rate compared to the death rate, and advances in technology that improved food and water supplies—directly contributed to population growth.