You find that the database performance degrades while you backup the PROD database using Recovery Manager （RMAN）. The PROD database is running in shared server mode. The database instance is currently using 60% of total operating system memory. You suspect the shared pool fragmentation to be the reason.
Which action would you consider to overcome the performance degradation？（）

A.Each segment contains one or more extents.
B.Multiple tablespaces can share single data file.
C.A data block is the smallest unit of I/O for data files.
D.It is possible to have tablespaces of different block sizes in a database.
E.Each data block in the database always corresponds to one OS block.

A.This clause is not valid for a temporary or undo tablespace.
B.If the tablespace is in the NOLOGGING mode， no operation on the tablespace will generate redo.
C.The tablespace will be in the NOLOGGING mode by default， if not specified while creating a tablespace.
D.The tablespace­level logging attribute can be overridden by logging specifications at the table， index， materialized view， materialized view log， and partition levels.

A.average row size
B.last analyzed date
C.size of table in bytes
D.size of table in database blocks
E.number of free blocks in the free list
F.number of extents present in the table