Explanation:
The main advantage of managed recovery mode is that the standby database automatically applies the archived redo log when the files become available to keep the target database and the standby database in synchronization.
Incorrect Answers:
1: The managed recovery mode of standby databases is not used just to avoid most common DBA errors.
2: Standby databases do not use prompts for applying the next available redo logs.
3: The primary database automatically ships archived redo log files to the standby server not because of managed recovery mode, but because of init.ora file initialization parameters of the primary database.
Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 1159
Chapter 24: Oracle8i New Features Topics

---