How is block-change tracking enabled?（）

A.Restore and recover the datafile. 
B.Restore and recover the tablespace. 
C.Restore and recover the database. 
D.Restore and recover the control file. 
E.Restore and recover the parameter file.

A.The system change number, which is a point in time relative to transactions within a given database. 
B.A number that represents time. Thus, at 1300 hours, the SCN is the same on all databases. 
C.The security change number, which represents the security code that is needed to access any database structure.
D.A conversion factor that converts internal database time to external clock time. 
E.UTC time in the database, providing a standardized way of tracking time in Oracle. 

A.Restore the backup copy of the tempfile from the backup media. 
B.Re-create the tempfile with the create tempfile command. 
C.Copy an existing tempfile from another database. 
D.Re-create the tempfile with the create tablespace command. 
E.Re-create the tempfile with the alter tablespace command.