The new technology produced in Detroit on an assembly line during the 1920s is option C) automobiles.
During the 1920s there was a rapid increase in car sales due to mass production techniques used by Henry Ford. The reasons why the car sales skyrocketed in the 1920s were high employment and economic power. Americans at the time had more money to spend on entertainment and luxury and cards came to raise the standards of living in American society after WWI.