Shortly after World War II, John Jackson developed and began selling a machine lubricant that was superior to anything currently on the market. While demand kept up with production at first, several strong competitors added new products and he soon had to hire a sales force to sell excess product manufacturing companies in the area. This is an example of marketing behavior that would occur during the _____ era of U.S. business history.

Multiple Choice

A. marketing concept

B. production

C. goods

D. Sales

E. social entrepreneurship