Who primarily comprises the members of a labor union?

The correct choice highlights that members of a labor union are primarily composed of workers who share common interests, such as similar job functions, industries, or workplace conditions. This collective grouping is fundamental to the concept of a labor union, which exists to represent and advocate for the rights, interests, and needs of its members. Unions enable workers to negotiate collectively for better wages, benefits, and working conditions, making unity among individuals with similar professional interests a key component.

The alternative options do not accurately capture the essence of union membership. Management employees typically represent the interests of the employer rather than the workers and are not usually included in labor unions. Independent contractors, while they may work in similar fields, often do not share the same employment relationship as traditional employees and may not have the same collective bargaining needs. Focusing solely on technicians disregards the diverse range of professions that can be represented within a labor union, which can include various roles across different industries, not limited to technical positions.