In your database, you want to ensure that idle sessions that are blocking active are automatically terminated after a specified period of time.
How would you accomplish this?（）

A. The MRKT tablespace is created as a small file tablespace, because the file size is less than the minimum required for big file files.
B. The MRKT tablespace may be dropped if it has no contents.
C. Users who were using the old default tablespace will have their default tablespaces changed to the MRKT tablespace.
D. No more data files can be added to the tablespace.
E. The relative file number of the tablespace is not stored in rowids for the table rows that are stored in the MRKT tablespace.

A. The database must have multiplexed redo logs for the flashback to succeed.
B. The database must be MOUNTED for the flashback to succeed.
C. The database must use block change tracking for the flashback to succeed.
D. The database must be opened in restricted mode for the flashback to succeed.
E. The database must be opened with the RESETLOGS option after the flashback is complete.
F. The database must be opened in read-only mode to check if the database has been flashed back to the correct SCN.

A. They are tied to a specific statement or SQL id.
B. They instruct the maintenance job to collect missing statistics or perform dynamic sampling to generate a more optimal plan.
C. They are used to gather only missing statistics.
D. They are created for a query expression where statistics are missing or the cardinality estimates by the optimizer are incorrect.
E. They instruct the optimizer to create only column group statistics.
F. Improve plan accuracy by persisting both compilation and execution statistics in the SYSAUX tablespace.