You perform differential incremental level 1 backups of your database on each working day and level 0 backupon 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 1 backup.
• C、The backup performed on each working day contains all the blocks that have changed since the last level 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