Upon starting your database， you receive the following error：   SQL> startup ORACLE instance started.  Total System Global Area 171581440 bytes Fixed Size 1298640 bytes Variable Size 146804528 bytes Database Buffers 20971520 bytes Redo Buffers 2506752 bytes Database mounted.  ORA-00313： open failed for members of log group 1 of thread 1  ORA-00312： online log 1 thread 1： ’/oracle01/oradata/orcl/redo01.log’ ORA-00312： online log 1 thread 1： ’/oracle01/oradata/orcl/redo01a.log’   You can choose from the following steps：   a. Restore the database datafiles.  b. Issue the alter database clear unarchived logfile group 1 command. c. Issue the alter database open command.  d. Issue the alter database open resetlogs command.  e. Recover the database using point-in-time recovery. f. Issue the Startup Mount command to mount the database.  g. Back up the database.  Which is the correct order of these steps in this case？（）

• A、a， f， e， d， g
• B、f， e， d
• C、f， b， c， g
• D、a， f， c
• E、The database cannot be recovered.