Explanation:
To reduce redo logs generating a DBA would load a table during a direct loaded operation using the NOLOGGING options. Specifying the NOLOGGING clause means that the creation of the table or index, as well data loaded into the table or index, will not generate any redo information. This enhances performance of data load or object creation operations, but leaves you with dilemma later if the database fails and you haven't taken a backup. Even if you archive your redo logs, you still will not be able to recover data, because no redo was generated for operations related to that object. Use NOLOGGING very sparingly, and only with table data load or index creation operations when you plan to take a backup very soon anyway.
Incorrect Answers:
1: Using the NOLOGGING option does not eliminate further backup, quite the contrary it requires DBA to take backup as soon as possible after load operations completion.
2: This option disable temporarily redo log generation, not collecting statistics.
4: The NOLOGGING option has nothing to do with the least recently-used end of the buffer cache.
Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 590-591
Chapter 12: Overview of Backup and Recovery

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