During regular database operation, which background process will take smaller blocks of free space in a dictionary-managed tablespace and move things around to make bigger pieces of free space?（）

A.OPTIMAL 
B.INITIAL 
C.PCTINCREASE 
D.NEXT

A.Issue ALTER DATABASE BACKUP CONTROLFILE TO filename
B.Make a copy of the control file with the database shut down
C.Issue ALTER DATABASE BACKUP CONTROLFILE TO trace
D.Make a copy of the control file with the database still running