Which technology is used by Unity Snapshots?

A.
Copy on First Write

B.
Inline Deduplication

C.
Redirect on Write

D.
Block Compression

Explanation:
The technology used for snapshots of both block and file resources in Unity is called redirect on write.
https://www.emc.com/collateral/white-papers/h15089-emc-unity-snapshots.pdf (page 6)