Explanation:
Closed database backup will not cause an additional generation of redo because this type of backup is just copying of closed datafiles on operation system level: it has nothing to do with redo logs.
Incorrect Answers:
1: Open database backup (hot backup) will cause redo log activity.
3: Increased transactional activity in the database will generate additional redo log files.
4: If you change the NOLOGGING mode on frequently updated tables to LOGGING redo logs will be definitely generated for these statements.
Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 585-591
Chapter 12: Overview of Backup and Recovery

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