What best defines a messenger in terms of property custody?

A messenger is best defined as an individual who has the care of property while it is outside the premises. This role involves the responsibility of transporting valuable items or property and ensuring its protection until it reaches its destination. Messengers are often entrusted with the safe handling of this property during transit, which can include cash, documents, or other tangible assets.

Understanding the role of a messenger is crucial in the context of property custody because it highlights the distinction between property that is actively managed on-premises and property that is in transit or outside the primary storage location. This definition aligns with the concept of custody in property management, where the authorized individual must maintain a duty of care for the property during its physical movement away from a secure location.

Other roles mentioned in the choices, such as insuring property within the premises, supervising physical inventory on-site, or acting as a trustee for access to common areas, do not accurately capture the unique responsibilities that define a messenger's role in relation to property custody.