What is the entity under which a security guard performs their duties?

The correct choice indicates that a security guard typically operates under a security company. This company employs the guards and provides the necessary training and resources for them to fulfill their duties effectively. The security company is responsible for assigning guards to various locations and ensuring that they adhere to industry standards and legal regulations.

The relationship is important because it establishes the framework for the guard's responsibilities, rights, and the level of authority they hold while on duty. Being part of a security company often includes benefits such as insurance, training programs, and operational support, which would not be available if the guard operated independently or for a different entity.

In contrast, the other options do not adequately capture the overarching structure and employment relationship that defines the role of security guards. The ownership of property or affiliation with government agencies does not directly relate to the organization under which the guard receives training and performs their authorizations and duties.