Explanation
According to the Huawei documents and resources, Huawei Agile Cloud Authentication (HACA) supports iMaster NCE-Campus as well as Agile Controller-Campus as the HACA server. HACA is an authentication method that allows users to access a network without entering user names or passwords3. Therefore, B is the correct answer. References: 3: https://support.huawei.com/enterprise/en/doc/EDOC1100086527

Explanation
According to the Huawei documents and resources, EAP termination and EAP relay are typical 802.1X authentication modes between the access device and authentication server. In EAP termination mode, the access device terminates EAP packets and encapsulates them into RADIUS packets. In EAP relay mode, the access device directly encapsulates the received EAP packets into RADIUS using EAP over RADIUS (EAPoR) packets2. Therefore, A and B are the correct answers. References:
https://support.huawei.com/enterprise/en/doc/EDOC1100086527

Explanation
According to the Huawei documents and resources, the VRRP preemption delay is the time that an AC waits before preempting another AC with a lower priority. If the VRRP preemption delay is set to a small value, the following problems may occur after a master/backup switchover:
B: A master/backup switchback is triggered too quickly. If the master AC recovers soon after a switchover, it may preempt the backup AC again and become the master AC. This may cause frequent switchovers and affect network stability C: Backup information is incomplete. If the backup AC takes over services from the master AC too quickly, it may not have received all the data synchronized from the master AC through HSB. This may cause service interruption or data loss Therefore, B and C are the correct answers. References:
https://support.huawei.com/enterprise/en/doc/EDOC1100064368/80fc2ebd/example-for-configuring-vrrp-hsb
2: https://support.huawei.com/enterprise/en/doc/EDOC1100096325/1a753937/vrrp-hsb-configuration

AP, WAC, and AC
With protocol trace, iMaster NCE-CampusInsight displays protocol-level interaction details at the AP, WAC, and AC phases for wireless users.
References: https://support.huawei.com/enterprise/en/doc/EDOC1100058940/8a8f1c9b/protocol-trace

Explanation
Navi WAC networking is a networking mode that uses a WLAN Access Controller (WAC) to manage and control APs. It can provide different authentication and security policies for different user groups, such as employees and guests. Guest data is isolated from the internal network to prevent security threats.
References: https://support.huawei.com/enterprise/en/doc/EDOC1100064352/9aadccc0/navi-wac-networking