You have an Azure subscription named Sub1 that contains the resources shown in the table. You create a user named Admin1. To which of the following can you add Admin1 as a co-administrator?

In Azure, the "co-administrator" role is a classic subscription-level role. This means it can only be assigned at the subscription scope. Therefore, Admin1 can be added as a co-administrator to Sub1. You cannot assign the co-administrator role to a resource group (RG1), a management group (MG1), or a virtual machine (VM1) directly. These resource types use Azure role-based access control (RBAC) for granular permissions, where you would assign built-in or custom RBAC roles like "Contributor" or "Owner" instead of the legacy co-administrator role.