Which action is taken to create a new subnet in Active Directory Sites and Services?

To create a new subnet in Active Directory Sites and Services, the correct action is to right-click on Subnets and select New Subnet. This is because the Subnets container specifically manages all the defined subnets that are associated with Active Directory. By adding a new subnet here, you allow the Active Directory to understand which IP addresses belong to which sites. This helps in optimizing network traffic and provides better site-specific services to users.

Subnets in Active Directory are linked to sites and provide direct information on the network configuration, enabling the domain controllers to make appropriate decisions based on the subnet memberships. Thus, creating a new subnet directly under Subnets ensures it is properly recognized and integrated within the Active Directory architecture. The other options do not align with the designated management structure of Active Directory, where management levels and their specific roles are clearly defined.