For which Symmetrix VMAX SRDF mode(s) is the SiRT feature used?

For which Symmetrix VMAX SRDF mode(s) is the SiRT feature used?

A.
SRDF/A and SRDF/S

B.
SRDF/A and SRDF/Adaptive Copy

C.
SRDF/A only

D.
SRDF/S only