Explanation:
Possibly one or more files are still recovering and it/they are in ACTIVE status. In the STATUS column of V$BACKUP view, ACTIVE indicates that the file is currently in backup mode. Incorrect Answer:
2: ONLINE status of the data file is normal working state of the data file.
3: Data file in OFFLINE state will not cause problems described in the question.
4: In the STATUS column of V$BACKUP, NOT ACTIVE indicates that the file is not currently in backup mode, so it will not affect the database performance.
Reference:
OCP Oracle 9i Database: Fundamentals II Exam Guide, Rama Velpuri, p. 303
Chapter 12: User-Managed Complete Recovery

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