SQL> grant all PRivileges to dba with admin option;
SQL> grant select_catalog_role to dba with admin option;
SQL> grant execute_catalog_role to dba with admin option;
SQL> grant delete_catalog_role to dba with admin option;
EXPlanation: ============
The DBA role is created at database creation time by the "sql.bsq" script. (The "sql.bsq" script is typically found in the $Oracle_HOME/dbs or the $ORACLE_HOME/rdbms/admin Directory.)
Additional grants are made to dba through other scripts in the admin directory.
For example, exp_full_database and imp_full_database in catexp.sql.
The above commands are excerpts from the "sql.bsq" script