Final answer:
The authority of security guards during a labor dispute comes from their status as representatives of the employer/property owner, allowing them to protect people and property and control access to the property.
Step-by-step explanation:
During a labor dispute, the authority of security guards to act to protect people and property from harm or loss, and to control access to the property involved, primarily comes from (A) their status as representatives of the employer/property owner. This authority is derived from their role to legally enforce the policies and protect the interests of their employer, rather than any special legal status granted by independent bodies or specific laws regarding labor disputes. The Labour Relations Act and other statutes establish the legal framework for labor disputes and union activities, but they do not typically grant direct authority to security guards. Similarly, while security guards may have the right to conduct a citizen's arrest under the Criminal Code in certain circumstances, this is not their primary source of authority in the context of a labor dispute. Furthermore, the Canadian Charter of Rights and Freedoms provides overarching rights and freedoms to individuals, but it does not specifically confer enforcement authority to security guards.
Ultimately, security guards acting during a labor dispute must navigate a complex interplay of property rights, the rights of individuals, and legal limitations to maintain order and safety without infringing on the rights of the disputing parties as outlined in various laws and regulations.