Exhibit， Viewing the Exhibit and examine the Flashback Database architecture. Identify the missing component （shown with a "？`"= in the Flashback Database architecture.（）

A. assign users to consumer groups
B. set the resource plan for the instance
C. configure a simple resource plan and specify plan directives
D. configure a complex resource plan and specify plan directives

A. It would result in an error because the warning threshold cannot be more than the critical threshold.
B. The warning threshold is ignored and alerts would be generated when space usage exceeds the critical threshold.
C. The critical threshold is ignored and alerts would be generated when space usage exceeds the warning threshold.
D. Both threshold values are used and alerts are generated when space usage exceeds the respective threshold values.

A. The user must have been granted the DBA role.
B. The user must have been granted the switch privilege as a part of a role.
C. The user must have been granted the Resource Manager administrator privilege.
D. The user must have been granted the switch privilege by using the DBMS_RESOURCE_MANAGER_PRIVS package.