Compare a typical Distributed Replicated Block Device (DRBD) with MySQL Standard Replication using master-slave replication. Which two statements are correct?（）

• A、Both technologies guarantee an identical copy of data on the secondary node
• B、Only MySQL can maintain a time-delayed copy of data on the secondary node
• C、Both technologies use the TCP/IP stack as their primary transmission medium
• D、DRBD uses shared-disk technology