Suppose terraformcode is taking up some values which are not defined inside the code files. In which of the following options issue might have occurred?

The main.tf file contains resource definitions and provider configuration; any value originating there is visible in the code and would not cause unexplained external values.

The vars.tf file declares variable blocks with optional defaults; any value originating there is explicitly defined in the code files.

The terraform.tfvars file is a standard variable definitions file that Terraform automatically loads, so values from it are fully traceable within the project directory.

Terraform supports reading variable values from environment variables named TF_VAR_ followed by the variable name, meaning a value can influence the configuration without appearing in any .tf or .tfvars file. If unexpected values are being consumed, the issue is likely an unintended or incorrect TF_VAR_* environment variable set in the shell or CI/CD environment.