Explanation:

The primary and most critical use of creating a backup in a database system is to enable data recovery in the event of data loss, corruption, hardware failure, or other disasters. When data is lost or becomes inaccessible, the backup serves as a copy that can be restored to retrieve the lost information, effectively allowing one to "find" or recover the lost data. Option (b) "For safety" is a general benefit, but option (d) describes the specific action and purpose when data has actually been compromised. Options (a) "To check the working of the system" and (c) "To provide record of transaction" are functions typically handled by system monitoring tools and transaction logs, respectively, not the primary role of a backup. Backups are a cornerstone of disaster recovery planning.