Explanation:
This command provides correct syntax for connection. Keyword TARGET shows the name of the target database, and keyword RCVCAT gives information about recovery catalog database.
Incorrect Answers:
1: This command does not include the TARGET keyword.
2: This command does not include mandatory RMAN keyword.
4: It's incorrect syntax command.
Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 619-620
Chapter 13: Using Recovery Manager for Backups

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