The suggested answer is D.
The ideal design for VMware Cloud Foundation domains should adhere to both the minimum requirements for a management domain and the best practices for vSAN clusters. A management domain typically requires at least 4 nodes. For workload domains, vSAN best practices recommend that the nodes within a cluster should have identical configurations, including the number and size of disk groups. Therefore, allocating 4 nodes with 1 vSAN disk group to a workload domain and 8 nodes with 2 vSAN disk groups to another workload domain ensures consistency and optimal performance, aligning with both management domain requirements and vSAN best practices.