Explanation:
The CHANGE command alters the availability status of a specified backup item. For backups, the BACKUP PIECE keyword is used. For archived redo logs, the ARCHIVELOG keyword is used. For an image copy, the DATAFILECOPY keyword is used. For a control file, the CONTROLFILECOPY keyword is used. The availability statuses that can be specified are DELETE, UNAVAILABLE, AVAILABLE and CATALOG.
Incorrect Answers:
2: The CHANGE command is missing the DELETE clause.
3: The CHANGE command is missing the DELETE clause. The FILE clause is used incorrectly in the ALLOCATE CHANNEL command.
4: The FILE clause is used incorrectly in the ALLOCATE CHANNEL command.
Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 623-626
Chapter 13: Using Recovery Manager for Backups

---