Which two are true about RMAN duplexed backup sets? (Choose two.) 

Answer options:

A. They can be written only to disk.
B. They must be written to media.
C. They can be created by using the RMAN CONFIGURE command to specify duplexing before taking a backup.
D. They can be created only by using the COPIES option of a BACKUP command.
E. They can be written to media.

DE

Reference: https://web.stanford.edu/dept/itss/docs/oracle/10gR2/backup.102/b14191/rcmconc1003.htm#:~:text=Duplexed%20Backup%20Sets,destinations% 20with%20one%20BACKUP%20command .