It should be RG4 and RG6 for both,
For creating the VNet, While the policy allows the creation and management of network security groups in RG4, it does not directly address the creation of virtual networks. Therefore, the creation of virtual networks should be allowed by default in RG4.
For RG6, the policy specifically prohibits the creation or modification of virtual network peerings but It does not mention anything about the creation of virtual networks themselves. As there is no explicit restriction on the creation of virtual networks, the creation of virtual networks should be allowed in RG6.
For the second part, creation of Network security group only being denied on RG5 and it's allowed for both RG4 and RG6.