Explanation/Reference:
D: By default Exadata stores only small I/Os in the Exadata Smart Flash Cache. Small I/Os in most cases are single-block reads. During a full table scan Oracle requests blocks in multiblock lumps (by default 16 blocks), and these are
Incorrect Answers:
C: Oracle has over time has almost completely eliminated caching of table scan blocks from the buffer cache and why by default Exadata does not cache full table scan blocks in the Exadata Smart Flash Cache.
During a full table scan Oracle requests blocks in multiblock lumps (by default 16 blocks), and these are not stored in the Exadata Smart Flash Cache unless you change the CELL_FLASH_CACHE clause for the segment.
References: http://www.informit.com/articles/article.aspx?p=2418151&seqNum=3

Metrics are a series of measurements that are computed and retained in memory for an interval of time, and stored on a disk for a more permanent history.
On the storage servers, the CELLSRV process provides the majority of Oracle Exadata storage services and is the primary storage software component. One of its functions is to process, collect, and store metrics. The Management Server (MS) process receives the metrics data from CELLSRV, keeps a subset of metrics in memory, and writes to an internal disk-based repository hourly.
References:
http://www.oracle.com/technetwork/articles/servers-storage-admin/monitor-exadata-em12-2291964.html

The default schedule of scrubbing is every two weeks.
References: http://docs.oracle.com/cd/E80920_01/DBMMN/maintaining-exadata-storage-servers.htm

Explanation/Reference:
Transportable database approach (TDB). If the source system is running Oracle 11.2 or above with Little Endian format, this method can be used to migrate the database to Exadata.
References: https://www.toadworld.com/platforms/oracle/w/wiki/11551.managing-troubleshooting-exadata- part-3-migrating-databases-to-exadata-database-machine-best-practices