The suggested answer is A, D.
To ensure that any virtual machines that are created are placed in the appropriate site in a vSAN Stretched Cluster, it is necessary to create VM/Host groups for the two sites. This allows for the definition of where VMs can be placed within the stretched cluster. Additionally, once the groups are created, the virtual machines need to be placed in the correct VM group. This ensures that VMs are correctly assigned to the site-specific groups, fulfilling the requirement to manage VM placement accurately.