*You can specify policies for ADO at the row, segment, and tablespace level when creating and
altering tables with SQL statements.
*(Not E, Not F) When Heat Map is enabled, all accesses are tracked by the in-memory activity
tracking module. Objects in the SYSTEM and SYSAUX tablespaces are not tracked.
*To implement your ILM strategy, you can use Heat Map in Oracle Database to track data access
and modification.
Heat Map provides data access tracking at the segment-level and data modification tracking at the
segment and row level.
*To implement your ILM strategy, you can use Heat Map in Oracle Database to track data access
and modification. You can also use Automatic Data Optimization (ADO) to automate the
compression and movement of data between different tiers of storage within the database.
Reference: Automatic Data Optimization with Oracle Database 12c
with Oracle Database 12c

Wait up to 600 seconds for required locks on SH.SALES:
EXECUTE DBMS_REDEFINITION.FINISH_REDEF_TABLE (
'SH', 'SALES', 'INT_SALES', 600);
Reference: http://oradb-srv.wlv.ac.uk/E50529_01/ARPLS/d_redefi.htm#ARPLS042

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?

Explanation/Reference:
Explanation:
C: During the first execution of a SQL statement, an execution plan is generated as usual.
D: if multi-column statistics are not present for the relevant combination of columns, the optimizer can fall back on cardinality feedback.
(not B)* Cardinality feedback. This feature, enabled by default in 11.2, is intended to improve plans for repeated executions.
optimizer_dynamic_sampling
optimizer_features_enable
* dynamic sampling or multi-column statistics allow the optimizer to more accurately estimate selectivity of conjunctive predicates.
Note:
* OPTIMIZER_DYNAMIC_SAMPLING controls the level of dynamic sampling performed by the optimizer.
Range of values. 0 to 10
* Cardinality feedback was introduced in Oracle Database 11gR2. The purpose of this feature is to automatically improve plans for queries that are executed repeatedly, for which the optimizer does not estimate cardinalities in the plan properly. The optimizer may misestimate cardinalities for a variety of reasons, such as missing or inaccurate statistics, or complex predicates. Whatever the reason for the misestimate, cardinality feedback may be able to help.

Backing Up a Whole CDB
Backing up a whole CDB is similar to backing up a non-CDB. When you back up a whole CDB, RMAN backs up the root, all the PDBs, and the archived redo logs. You can then recover either the whole CDB, the root only, or one or more PDBs from the CDB backup.
Note:
*You can back up and recover a whole CDB, the root only, or one or more PDBs.
*Backing Up Archived Redo Logs with RMAN
Archived redo logs are the key to successful media recovery. Back them up regularly. You can back up logs with BACKUP ARCHIVELOG, or back up logs while backing up datafiles and control files by specifying BACKUP ... PLUS ARCHIVELOG.