In the park scenario, what is correct about the policy linkage function?

In the park scenario, what is correct about the policy linkage function?
A . When the authentication point and the group policy execution point are not on the same device, you need to use the policy linkage function.
B . In the policy linkage scenario, it is necessary to set the downlink port type of the Edge device to an extended access switch.
C . The policy linkage function means that no matter where you go, the permissions to access resources are the same and are decoupled from the IP address.
D . When the authentication point, access point, and group policy execution point are all connected to the access device, the policy linkage function must be used.

Answer: B