The main reason for the trend toward decentralization of bargaining in the U.S. is:

A) Employers have been able to use their superior bargaining leverage to force decentralization.
B) Unions' preferences for more control and rigidity in the bargaining process.
C) Employee desires for less demanding work.
D) Employee desires for less responsibility associated with employee involvement.

The trend toward decentralization of bargaining in the U.S. is primarily driven by employers' desire for more control over the bargaining process. They have been able to use their superior bargaining leverage to force unions to accept decentralized bargaining, often by threatening to move operations to more favorable locations or hiring replacement workers. In many cases, employers have also been successful in convincing employees that decentralization will give them more flexibility and better opportunities for advancement. While unions may prefer a more centralized bargaining process, they are often willing to accept decentralization if it means retaining their ability to represent workers in the workplace.