Which of the following software features/products are available at additional cost for the StorwizeV7000?（）

• A、 Thin Provisioning, Easy Tier, FlashCopy 
• B、 FlashCopy, Fastback for Storwize, External Virtualization 
• C、 Easy Tier, TPC for Disk Midrange Edition, TPC for Replication 
• D、 TPC for Disk Midrange Edition, TPC for Replication, External Virtualization