A.A role can be granted to itself.
B.Roles are owned by the SYS user.
C.Roles can be granted to other roles.
D.A role cannot be assigned external authentication.
E.A role can contain both system and object privileges.

A.Perform point-in-time recovery to 2： 00 p.m.
B.Use Flashback Table feature to revert the changes.
C.Restore the entire database from the recent backup and open it.
D.Issue the rollback statement with system change number （SCN）.