You enabled the flashback logging feature， but you have not specified the location of the flash recovery area.  Which location would be used as the default location for the flash recovery area？（）

• A、the location used for control files
• B、the location used for redo log files
• C、the location set by using $ORACLE_BASE
• D、the location set by using $ORACLE_HOME
• E、the location set by using CORE_DUMP_DEST
• F、the location set by using BACKGROUND_DUMP_DEST