About the description of deployment of Huawei dual active data center network layer, which is correct? (Multiple Choice)

About the description of deployment of Huawei dual active data center network layer, which is correct? (Multiple Choice)
A . Huawei CloudEngine series data center switches are used as core switches.
B . The data center uses a typical Layer 2 or Layer 3 physical architecture network. The core switch is aggregated to access the WDM device through the CSS+ link.
C . Each site deploys a separate GSLB to achieve load balancing between sites.
D . Two SLBs are deployed at each site to form an HA cluster to implement load balancing of application layer servers.

Answer: ABCD