A user sends you an email with the following error message： create table idtable（id number） * ERROR at line 
1： ORA- 01110： data file 4： ，，/oracle01/oradata/orcl/users01.dbf ORA-27041： 01116： error in opening database file 4 ORA-unable to open file Linux Error： 
2： No such file or directory Additional information： 
3 You can choose from the following steps：
a. Restore the missing database datafiles. 
b. Take the missing datafile offline. 
c. Shut down the database. 
d. Issue the recover tablespace USERS command. 
e. Issue the Startup Mount command to mount the database.
f. Bring the USERS tablespace online. 
g. Issue the alter database open command. 
Which is the correct order of these steps in this case？（）

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？（）