单选题
The garment industry is labor-intensive; the production of garments requires the employment of a relatively large number of people. The auto industry is capital-intensive; a large amount of money is invested in elaborate equipment run by a relatively small number of people. If fringe benefits are not considered, a typical United States garment worker in 1979 earned 46 percent of a typical auto worker's wages. Which of the following, if true, is likely to be among the factors that account for the disparity between auto workers' and garment workers' wages?