According to the original topology and service-planning question, the required VLANs are VLAN 100 , VLAN 101 , and VLAN 102 , so options A , B , and C are correct. In HCIA-Datacom campus design questions, VLAN planning is usually based on service separation, such as user services, voice services, wireless services, management services, or specific departmental segmentation. Each service type is assigned an appropriate VLAN so that broadcast domains are separated and policies can be applied more effectively.

The reason option D is not selected is that it does not match the service requirements shown in the original figure. VLAN planning must follow the actual service design rather than arbitrary numbering. HCIA-Datacom emphasizes that campus VLAN planning should align with traffic isolation, gateway design, security policy deployment, and future scalability. Proper VLAN assignment helps simplify troubleshooting, reduce unnecessary broadcasts, and support service-based policy enforcement. This question tests the ability to read a service topology and identify which VLANs are actually required by the depicted design rather than choosing extra VLANs that are not part of the planned campus solution.