多项选择题 Whichofthefollowingarecorrectaboutblockmediarecovery？（）

多项选择题 Which two statements are true about the duplexing of the backups taken by RMAN? （）(Choose two.)

单项选择题 The following databases are registered in the base recovery catalog： PROD1， PROD2， and PROD3. The database user CATOWNER owns the base recovery catalog. You want a new user VPC1 to have access to only the PROD1 database and create a virtual private catalog. Given below are some of the commands required to achieve this：   1.SQL> GRANT recovery_catalog_owner TO vpc1； 2.RMAN> CONNECT CATALOG vpc1/password@catdb；  3.RMAN> GRANT CATALOG FOR DATABASE prod1 TO vpc1； 4.RMAN> CONNECT CATALOG catowner/password@catdb；  5.RMAN> CREATE VIRTUAL CATALOG；   What is the correct sequence in which the commands have to be executed？（）