What is the difference between discretionary access control (DAC) and role-based access control (RBAC)?

What is the difference between discretionary access control (DAC) and role-based access control (RBAC)?
A . DAC requires explicit authorization for a given user on a given object, and RBAC requires specific conditions.
B . RBAC access is granted when a user meets specific conditions, and in DAC, permissions are applied on user and group levels.
C . RBAC is an extended version of DAC where you can add an extra level of authorization based on time.
D . DAC administrators pass privileges to users and groups, and in RBAC, permissions are applied to specific groups

Answer: A