In 802.

According to the Huawei documents and resources, 802.1X authentication using port-based access control is a method that allows only one user to access the network through a po rt at a time. If a user is authenticated successfully on a port, subsequent users on this port can access the network without authentication.  When the authenticated user goes offline, all other users are denied access to the network 1 .  Therefore, A is the correct answer. References:  1 : https://support.huawei.com/enterprise/en/doc/EDOC1100086527