To answer this question, you need to understand the different backup formats used for database backups.
Option A) backup set only - This option is correct because a backup set is a logical backup format that can be written to tape. It includes all the necessary data and metadata to restore the database.
Option B) image copy only - This option is incorrect because an image copy is a physical backup format that cannot be written directly to tape. It is a bit-for-bit copy of the database files and is typically used for faster recovery.
Option C) only user-managed backup - This option is incorrect because it does not specify a specific backup format. User-managed backup refers to the process of manually performing backups, but it does not specify the format.
Option D) both image copy and backup set - This option is incorrect because although both backup sets and image copies are valid backup formats, only the backup set can be used for writing to tape as specified in the question.
Option E) only incremental image copy backup - This option is incorrect because it specifies a specific type of backup (incremental image copy) rather than a format. Incremental backups only copy the changes made since the last backup and do not provide a full backup of the database.
Therefore, the correct answer is option A) backup set only. This option is correct because a backup set is a logical backup format that can be written to tape.