Which of the Following Is NOT a Factor That Has

Multiple Choice

Which of the following is NOT a factor that has contributed to declining private-sector differential between union and nonunion wages in the U.S. since 1980?

A) Globalization of the production process
B) Improved ability of firms to substitute capital for labor in production
C) Adoption of two-tiered wage and benefit structures by unionized firms
D) Declines in the unemployment and health insurance premiums paid by union workers