Which one of the following statements regarding RBAC $($Role$-$Based Access Control$)$ is CORRECT?

a$.$

RBAC allows a network administrator to base privileges and permissions around a detailed description of a user's roles or jobs.

b$.$

RBAC allows users to decide for themselves who has access to that user's resources.

c$.$

RBAC organizes resources into hierarchical classifications, such as "confidential" or "top secret".

d$.$

RBAC is the most restrictive method of access control.