Explanation:
You need to back up of control file when you add or remove table spaces, datafiles, or online redo log groups or members, or when you rename any file in your Oracle database. You also need to take a backup of your control file if you change the archiving status of your database. Furthermore, you should back up the control file whenever you drop table spaces or change them from read-write to read-only state, or vice-versa.
Incorrect Answers:
1: You don't need to back up your control file after ALTER TABLE command.
2: You don't need to back up your control file after CREATE TABLE command.
4: You don't need to back up your control file after creation of rollback segment.
Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 591-593
Chapter 12: Overview of Backup and Recovery

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