In U.S. business history, the marketing concept became a motivating force during Marketing In U.S. business history, the marketing concept became a motivating force during a. the 1950s. b. the first few years of the 21st century. c. the 1920s. d. the mid-1980s. e. the early years of the Civil War. Answer: a. the 1950s. Learn More : Share this Share on FacebookTweet on TwitterPlus on Google+