What are two valid reasons for doing this?

You plan to disable automatic tier relocation of certain HDT volumes in Hitachi Dynamic Tiering.

What are two valid reasons for doing this? (Choose two.)
A . To ensure prioritization of a volume whose I/O activity is constant.
B . To ensure prioritization of a volume whose size is growing exponentially.
C . To ensure prioritization of a volume whose I/O activity varies greatly.
D . To ensure prioritization of a critical volume whose I/O workload is low.

Answer: C,D