The correct answers are A and C. To update a registry module from version 4.2.1 to 5.0.0, you must first update the module block’s version argument so Terraform knows which module version is required. After changing the module version constraint, you must reinitialize the working directory so Terraform can install the selected module version into the local .terraform directory. In many real workflows, terraform init is sufficient after changing the version, while terraform init -upgrade is commonly used when refreshing already-installed modules to newer acceptable versions. terraform pull is not a Terraform command for updating modules. Removing the version argument is not a controlled upgrade because Terraform may then choose the newest available version, which can reduce reproducibility and increase upgrade risk.