Which statement is true about BTRFS RAID?

Which statement is true about BTRFS RAID?

A.
BtrfsRAID is a multi-disk software RAID providing the same functionality as a software RAID created using themdadmcommand.

B.
BtrfsRAID is block device RAID.

C.
BtrfsRAID is mirroring block devices.

D.
BtrfsRAID just ensures that for every block, there are “x” number of copies.