Which of the following best defines labor law?

Labor law is best defined as the body of regulations that govern the rights and duties associated with employment. This encompasses a wide range of topics, including workplace rights, employee benefits, collective bargaining, and regulations concerning workplace safety and discrimination. The scope of labor law is comprehensive, as it applies to both individual employees and groups, addressing issues relevant to the employer-employee relationship.

The other options presented in the question are too narrow in their scope. Focusing solely on safety regulations or limiting the definition to rules enforced by trade unions excludes significant aspects of labor law, such as wage regulations and anti-discrimination laws. Additionally, confining labor law to public sector employees disregards its application to private sector workers as well. Thus, the correct definition captures the full breadth of labor law's impact on the workplace and employee relations.