In which two ways does Optimized Single Instance Storage (OSIS) save storage space? (Select two.)

A.
The SIS parts are shared between the Vault Stores in the same sharing boundary.

B.
SIS identifies the SIS part from the filename.

C.
Attachments are stored once within a sharing boundary.

D.
The SIS parts are shared between the Vault Stores in different sharing boundaries.

E.
Attachments are stored only once in a different sharing boundary.