Final answer:
The three cigarette brands that emerged as market leaders following the breakup of James Duke's American Tobacco Company monopoly in 1911 were likely Liggett & Myers, Lorillard, and R.J. Reynolds. These brands became significant competitors in the tobacco industry which James Duke had earlier monopolized, shaping the cigarette market and consumer culture.
Step-by-step explanation:
The three cigarette brands that dominated the market during the early part of the 20th century, following the dissolution of James Duke's tobacco monopoly in 1911, were likely the resulting companies from the breakup of the American Tobacco Company. While specific brand names from this era are not provided in the question or the reference material, it's known that the splitting of Duke's company led to the creation of several major tobacco companies, such as Liggett & Myers, Lorillard, and the R.J. Reynolds Tobacco Company. These companies became influencers in the market, engaged in competition for market leadership, and played significant roles in the development of the cigarette industry as we know it.
Duke's aggressive marketing strategies, production innovations, and pricing tactics raised the popularity of cigarette smoking in America, rehabilitating its image and embedding it in working-class culture, despite the health risks that were becoming increasingly evident through studies conducted by researchers like Richard Doll and Austin Bradford Hill.