You perform differential incremental level 1 backups of your database on each working day and level 0 backup on Sundays， to tape. Which two statements are true about differential incremental backups（）

A. The backup performed on Sundays contains all the blocks that have ever been used in the database.
B. The backup performed on Sundays contains all the blocks that have changed since the last level 1backup.
C. The backup performed on each working day contains all the blocks that have changed since the lastlevel 0 backup.
D. The backup performed on Monday contains all the blocks that have changed since the level 0 backup，and every other working day contains all the blocks that have changed since the level 1 backup.