Final answer:
The Mandatory Access Control (MAC) model requires labels as a component to determine permissions based on user clearance and data classification. These labels are essential to MAC's security framework and are not to be confused with certificates, tokens, or RBAC, which relate to other access control models.
Step-by-step explanation:
When using the Mandatory Access Control (MAC) model, the component that is needed is labels. MAC relies on these labels (sometimes called security labels) to enforce access controls. In this context, labels are attached to resources and users to determine permissions based on their clearance level and the classification of the information.
Each object, such as a file or data packet, is assigned a label indicating its security level, and each user's access permissions are determined by their own clearance level. Only those users with appropriate clearance can access certain levels of data, creating a highly secure environment by strictly enforcing access based on these security labels.
Certificates, tokens, and Role-Based Access Control (RBAC) are elements of other access control models and are not the necessary components for MAC. The correct answer is A) LABELS.