Which access control method requires users to have explicit permission granted by an administrator?

Discretionary Access Control (DAC) is characterized by the principle that access to resources is determined by the owner or administrator of those resources. In this system, users must receive explicit permission from an administrator to gain access to a particular resource or system. This flexibility allows resource owners to make decisions about who can access their resources, promoting a more individualized approach to access management.

In contrast, other access control methods function differently. Mandatory Access Control (MAC) relies on a centralized authority that sets strict policies under which users operate, rather than individual permissions; this can restrict user flexibility. Role-Based Access Control (RBAC) assigns access rights based on the user’s role within the organization, focusing on job responsibilities and not explicit user permissions. Lastly, Physical Control pertains to physical barriers and security measures that restrict access to buildings or assets rather than electronic or system-level permissions.

Thus, the emphasis on explicit permission in Discretionary Access Control makes it the correct choice in this context.