In Recovery Manager （RMAN）， you are taking image copies of the datafiles of your production database and rolling them forward as regular intervals. You attempt to restart your database instance after a regular maintenance task， you realize that one of the data files that belongs to the USERS tablespace is damaged and you need to recover the datafile by using the image copy. You could perform the following steps to accomplish this：   1） Mount the database  2） Take the data file offline  3） Bring the data file online  4） Use the RMAN SWITCH TO command to switch the image copy  5） Apply the archived redo logs  6） Open the database  7） Use the RMAN RESTORE TO command to switch to the image copy   Which two options illustrate the correct sequence of steps that you could follow？（）

• A、 2， 6， 4， 5， 3
• B、 1， 2， 4， 5， 3， 6
• C、 1， 2， 4， 6， 3
• D、 1， 2， 7， 5， 3， 6