This is the meta-argument that you must include in any non-default provider configurations, as it allows you to give a friendly name to the configuration and reference it in other parts of your code. The other options are either invalid or irrelevant for this purpose.

Infrastructure as Code (IaC) can indeed be stored in a version control system along with application code. This practice is a fundamental principle of modern infrastructure management, allowing teams to apply software development practices like versioning, peer review, and CI/CD to infrastructure management. Storing IaC configurations in version control facilitates collaboration, history tracking, and change management.
Reference = While this concept is a foundational aspect of IaC and is widely accepted in the industry, direct references from the HashiCorp Terraform Associate (003) study materials were not found in the provided files. However, this practice is encouraged in Terraform's best practices and various HashiCorp learning resources.

The terraform plan command is used to create an execution plan. It allows you to see what actions Terraform will take to reach the desired state defined in your configuration files. It evaluates the current state and configuration, showing a detailed outline of the resources that will be created, updated, or destroyed. This is a critical step in the development process as it helps you verify that the changes you are about to apply will perform as expected, without actually modifying any state or infrastructure.
Reference:
Terraform documentation on terraform plan: Terraform Plan

These are the parameters that terraform import requires, as they allow Terraform to identify the existing resource that you want to import into your state file, and match it with the corresponding configuration block in your files.

terraform init is the first command that should be run after writing a new Terraform configuration or cloning an existing one from version control. It initializes a working directory containing Terraform configuration files and downloads any required providers and modules. The other commands are used for different purposes, such as importing existing resources, switching between workspaces, generating execution plans, etc.