Explanation:
You should apply redo log changes if the table space being recovered is writeable, but was readonly when the last backup occurred or when the table space being recovered is read-only, but was writeable when the last backup occurred..
Incorrect Answers:
1: If the table space being recovered has always been writeable, it is not in read-only mode.
2: You cannot apply redo logs to the table space being recovered is unknown to the control file.
3: If the table space being recovered is read-only and was read-only when the last backup occurred you don't need to apply redo logs to it, because there are no changes to it.
Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 593
Chapter 12: Overview of Backup and Recovery

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