B:Through initialization parameters, you specify the file system directory to be used for a particular type of file. The database then ensures that a unique file, an Oracle-managed file, is created and deleted when no longer needed.
D: The database internally uses standard file system interfaces to create and delete files as needed for the following database structures:
Tablespaces Redo log files Control files Archived logs Block change tracking files Flashback logs RMAN backups
Note: *Using Oracle-managed files simplifies the administration of an Oracle Database. Oracle-managed files eliminate the need for you, the DBA, to directly manage the operating system files that make up an Oracle Database. With Oracle-managed files, you specify file system directories in which the database automatically creates, names, and manages files at the database object level. For example, you need only specify that you want to create a tablespace; you do not need to specify the name and path of the tablespace's datafile with the DATAFILE clause.
Reference:What Are Oracle-Managed Files?