问题：

[单选] You have joined a new organization as a Database Administrator. The Security Administrator in your organization has kept human errors， such as erroneously dropping users， tables， and important data， to a minimum by carefully granting only the necessary privileges to each user. As a result of several ongoing transactions within your database， you discover that the flashback logs are rapidly increasing in the flash recovery area. To avoid out-of-space errors， you decide to delete the flashback logs from the flash recovery area. How can you delete the flashback logs from the database if your database is up and running？（）

A .  Shut down the database using the SHUTDOWN command. Mount the database using the STARTUP MOUNT EXCLUSIVE command and disable Flashback Database using the ALTER DATABASE FLASHBACK OFF statement.
B .  Change the parameter setting in the SPFILE for the DB_RECOVERY_FILE_DEST parameter using the ALTER SYSTEM SET DB_RECOVERY_FILE_DEST=’’ SCOPE=BOTH statement while the database is up and running.
C .  Shut down the database using the SHUTDOWN command. Mount the database using the STARTUP MOUNT EXCLUSIVE command. Change the parameter setting in the SPFILE for the DB_RECOVERY_FILE_DEST parameter using the ALTER SYSTEM SET DB_RECOVERY_FILE_DEST=’’ SCOPE=BOTH statement. Disable Flashback Database using the ALTER DATABASE FLASHBACK OFF statement.
D .  Change the parameter setting in the SPFILE for the DB_RECOVERY_FILE_DEST parameter using the ALTER SYSTEM SET DB_RECOVERY_FILE_DEST=’’ SCOPE=BOTH statement. Shut down the database using the SHUTDOWN command. Mount the database using the STARTUP MOUNT EXCLUSIVE command and disable Flashback Database using the ALTER DATABASE FLASHBACK OFF statement.