A . All the output values are available after a successful terraform apply command. This means that after the deployment, you can view the output values by running terraform output or terraform show in the same directory where you ran terraform apply1. You can also use the output values in other Terraform configurations or external systems by using the terraform output command with various options2. B. The subnet_private_1 value is defined in the variables.tf file. This means that the subnet_private_1 value is an input variable that can be customized by passing a different value when running terraform apply or by setting an environment variable3. The variables.tf file is where you declare all the input variables for your Terraform configuration4.
The other options are incorrect because:
After the deployment, Terraform output values are not visible only through AWS CloudShell. You can access them from any shell or terminal where you have Terraform installed and configured with your AWS credentials.
You do not need to specify all the AWS credentials in the output.tf file. The output.tf file is where you declare all the output values for your Terraform configuration4. You can specify your AWS credentials in a separate file, such as provider.tf, or use environment variables or shared credentials files. Reference:
Output Values - Configuration Language | Terraform - HashiCorp Developer Command: output - Terraform by HashiCorp Input Variables - Configuration Language | Terraform - HashiCorp Developer Configuration Language | Terraform - HashiCorp Developer

A . Use the terraform destroy command. This command is used to remove all the resources that were created using the Terraform configuration1. It is the opposite of the terraform apply command, which is used to create resources. The terraform destroy command will first show a plan of what resources will be destroyed, and then ask for confirmation before proceeding. The command will also update the state file to reflect the changes. D. The administrator must manually delete the Linux server. This is because the Linux server was not deployed using Terraform, but using AWS Marketplace2. Therefore, Terraform does not have any information about the Linux server in its state file, and cannot manage or destroy it. The administrator will have to use the AWS console or CLI to delete the Linux server manually.
The other options are incorrect because:
There is no terraform validate command. The correct command is terraform plan, which is used to show a plan of what changes will be made by applying the configuration3. However, this command does not delete any resources, it only shows what will happen if terraform apply or terraform destroy is run.
There is no terraform destroy all command. The correct command is terraform destroy, which will destroy all the resources in the current configuration by default1. There is no need to add an all argument to the command.

Multiple FortiGate-VM instances form an Auto Scaling group to provide highly efficient clustering at times of high workloads. FortiGate-VM instances can be scaled out automatically according to predefined workload levels.