You can configure a backend in your Terraform code before initializing it. Initializing a backend will store the state file remotely and enable features like locking and workspaces. References = [Terraform Backends]

The correct way to reference an attribute from the vsphere_datacenter data source for use with the datacenter_id argument within the vsphere_folder resource in the following configuration is data.vsphere_datacenter.dc.id. This follows the syntax for accessing data source attributes, which is data.TYPE.NAME.ATTRIBUTE. In this case, the data source type is vsphere_datacenter, the data source name is dc, and the attribute we want to access is id. The other options are incorrect because they either use the wrong syntax, the wrong punctuation, or the wrong case.
References = [Data Source: vsphere_datacenter], [Data Source: vsphere_folder], [Expressions: Data Source References]

terraform validate does not confirm that your infrastructure matches the Terraform state file. It only checks whether the configuration files in a directory are syntactically valid and internally consistent3. To confirm that your infrastructure matches the Terraform state file, you need to use terraform plan or terraform apply with the
-refresh-only option.

The correct syntax to pass a variable from the root module to a child module is servers = var.num_servers. Terraform uses dot notation to reference variables.
Reference:
Terraform Variables

These are some of the benefits of using Sentinel with Terraform Cloud/Terraform Enterprise, as they allow you to implement logic-based policies that can access and evaluate the Terraform plan, state, and configuration. The other options are not true, as Sentinel does not manage cloud access keys, and Sentinel policies are written in Sentinel language, not HCL.