You want to migrate your database to ASM， so you have done a clean shutdown， made a closed backup of the entire You wa database， noted the location of your control files and online redo log files， and changed your spfile to use OMF. The last step is to run an RMAN script to do the conversion. 
Using the following steps，what is the correct order in which the following RMAN commands should be executed？（）  
1. STARTUP NOMOUNT 
2. ALTER DATABASE OPEN RESETLOGS 
3. SQL "ALTER DATABASE RENAME ，，logfile1 path TO ，，+dgrp4 ，，" # plus all other logfiles 
4. SWITCH DATABASE TO COPY 
5. BACKUP AS COPY DATABASE FORMAT ，，+dgrp4
6. ALTER DATABASE MOUNT 
7. RESTORE CONTROLFILE FROM ，，controlfile_location

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