Which of the following are features of Btrfs ? A. relocating files and subtrees online B. removing and adding devices online c. running filesystem checks & scrubs online D. multiple file systems (subvolumes) within a single partition Solution features of Btrfs from given question are: a) relocating files and subtrees online c)running filesysytem checks and scrubs online d) multiple file system(sub volumes)with in a single partition. some more features of Btrfs are: 1. Extent based file storage 2. Space-efficient packing of small files 3. Space-efficient indexed directories 4. Dynamic inode allocation 5. Writable snapshots, read-only snapshots 6. Subvolumes (separate internal filesystem roots) 7. Checksums on data and metadata (crc32c) 8. Efficient Incremental Backup 9. Background scrub process for finding and fixing errors on files with redundant copies 10. Online filesystem defragmentation 11. Offline filesystem check 12. n-place conversion of existing ext3/4 file systems 13. Subvolume-aware quota support .