题目内容：
You are managing a 24*7 database. The backup strategy for the database is to perform user-managed backups. Identify two prerequisites to perform the backups.（）A． The database must be opened in restricted mode.
B． The database must be configured to run in ARCHIVELOG mode.
C． The tablespaces are required to be in backup mode before taking the backup.
D． The tablespaces are required to be in read-only mode before taking the backu
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