Which of the following is NOT considered an unfair labor practice?

Engaging in collective bargaining is not considered an unfair labor practice; in fact, it is a fundamental right protected under labor law. Collective bargaining refers to the process where employers and unions negotiate terms of employment, such as wages, hours, and working conditions. This process is seen as a constructive and legally protected interaction between labor and management, aiming to reach agreements that benefit both parties and promote workplace harmony.

In contrast, the other options involve actions that violate employees' rights under labor laws. Discriminating against employees for union membership and retaliating against employees for union activities both undermine the essence of collective bargaining and workers’ rights to organize. Similarly, interfering with the formation of a union directly obstructs the employees' ability to come together to negotiate for their interests. Therefore, these actions are identified as unfair labor practices, while engaging in collective bargaining is recognized as a legitimate and necessary component of labor relations.