Explanation:
RMAN works through external procedures. RMAN is used to manage the creation of database backups for the purpose of recovery. RMAN can be run as its own utility, or the functionality of RMAN in the form of a set of library functions can be embedded into another program or script.
Incorrect Answers:
1: RMAN does not work through PL/SQL packages.
3: Recovery manager does not work via operating system scripts.
4: RMAN does not use operating system commands.
Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 611-615
Chapter 13: Using Recovery Manager for Backups

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