Which of the following is a strategy employers might use to prevent unionization?

The strategy of having employees sign "yellow-dog contracts" is historically associated with attempts by employers to prevent unionization. These contracts are agreements wherein employees pledge not to join or support a union as a condition of employment. By requiring these agreements, employers aim to create an environment where union activity is discouraged, as any support or involvement in a union could lead to a breach of their contract and potential job loss.

This approach reflects a more adversarial tactic used by some employers to maintain control over their workforce and prevent the collective bargaining process associated with union representation. Recognizing the implications of such contracts in labor relations history is crucial; they are often viewed as coercive measures that undermine employees' rights to organize.

In contrast, promoting collective bargaining agreements or providing profit-sharing plans are strategies that can actually foster a collaborative environment between employers and employees and may lead to greater satisfaction and engagement rather than resistance to unionization. Providing full transparency in labor relations encourages open communication and trust, which can also work against the need or desire for union representation, but these strategies do not directly operate to prevent unionization in the same confrontational manner as yellow-dog contracts do.