Which type of backup must be performed first with an incremental backup？（）

单项选择题Whichtypeofbackupbacksuponlydatablocksmodifiedsincethemostrecentbackupatthesamelevelorlower？（）

A. Differential incremental backup
B. Different incremental backup
C. Cumulative backup
D. Cumulative incremental backup

单项选择题Whichisthecorrectcommandtobackupthedatabase，backupthearchivedredologs，andthenremovethebacked-uparchivedredologs？（）

A. backup database
B. backup database and archivelogs
C. backup database plus archivelogs
D. backup database plus archivelog delete input
E. backup database and archivelog delete input

单项选择题Compressedbackupsworkwithwhichofthefollowingcommands？（）

A. copy as backup
B. backup as copy
C. backup
D. copy

单项选择题Consider the following command：  Backup database plus archivelog delete input；  How many backup sets would be created by this command if the following were true：（）  Control-file a NN uto backups were enabled.  NN The size of backup sets was not restricted.  NN One channel was allocated.

A. 1
B. 2
C. 3
D. 4
E. 5

单项选择题WhattypeofbackupisstoredinaproprietaryRMANformat？（）

A. Backup set
B. Image copy
C. Backup section
D. Backup group