This is how the Terraform Cloud integration differs from other state backends such as S3, Consul, etc., as it allows you to perform remote operations on Terraform Cloud's servers instead of your local machine. The other options are either incorrect or irrelevant.

Terraform creates the .terraform.lock.hcl file after the first terraform init command. This lock file ensures that the dependencies for your project are consistent across different runs by locking the versions of the providers and modules used.

The terraform state file is locked when a Terraform operation that could write state is in progress. This prevents concurrent state operations that could corrupt the state. The forbidden actions when the state file is locked are those that could write state, such as terraform apply, terraform destroy, terraform refresh, terraform taint, terraform untaint, terraform import, and terraform state *. The terraform validate command is also forbidden, because it requires an initialized working directory with the state file. The allowed actions when the state file is locked are those that only read state, such as terraform plan, terraform show, terraform output, and terraform console. Reference = [State Locking] and [Command: validate]

The Terraform Registry allows any user to publish and share modules. Published modules support versioning, automatically generate documentation, allow browsing version histories, show examples and READMEs, and more. Public modules are managed via Git and GitHub, and publishing a module takes only a few minutes. Once a module is published, releasing a new version of a module is as simple as pushing a properly formed Git tag1.
Reference = The information can be verified from the Terraform Registry documentation on Publishing Modules provided by HashiCorp Developer1.

To import existing resources into Terraform, you need to do two things1:
Write a resource configuration block for each resource, matching the type and name used in your state file.
Run terraform import for each resource, specifying its address and ID. There is no such command as terraform Import-gcp, and provisioning new VMs with the same names will not import them into Terraform.