What is the primary function of a trade union?

The primary function of a trade union is to represent employee views and interests. Trade unions are established with the main purpose of advocating for workers' rights, which includes negotiating wages, working conditions, and hours, as well as addressing grievances. This representation ensures that employees have a collective voice in discussions with employers, allowing them to partake in decisions that directly affect their employment and working conditions.

While some trade unions may also focus on increasing salaries, that is just one aspect of their broader role in advocating for all aspects of employee welfare. The other choices mention functions that are either too narrow or not directly associated with the core mission of a trade union. For example, reviewing company policies and recruiting new employees may be tasks related to human resources or management rather than the advocacy role that defines trade unions. Thus, the comprehensive role of a trade union as a representative of employee interests makes the first option the correct answer.