Final answer:
Workers in the labor union movement used collective bargaining, strikes, and boycotts as primary tactics against their employers to fight for better working conditions and wages. Option C.
Step-by-step explanation:
Throughout the development of the labor union movement in the United States, workers employed various strategies against their employers to improve working conditions and secure better wages.
One of the primary tools they utilized was collective bargaining, a process in which workers, through their unions, negotiate with their employers to reach a mutually beneficial agreement.
However, when negotiations failed or were not an option, workers often resorted to strikes, a form of protest where they stopped working in an effort to put pressure on their employers to concede to their demands.
Boycotts were another tactic used by unions and workers. A boycott involves refusing to buy or use products and services from a particular company as a protest against its policies or actions, thereby harming the employer's business and compelling them to negotiate.
Option c.