When does terraform apply reflect changes in the cloud environment?

The correct response to when Terraform apply reflects changes in the cloud environment is that it occurs however long it takes the resource provider to fulfill the request. This means that after executing the terraform apply command, Terraform doesn't instantly update resources; rather, it sends requests to the respective cloud provider's API to create, update, or delete resources as specified in the Terraform configuration files.

The time it takes for changes to be reflected in the cloud environment is dependent on the provider's system and how quickly it can process the request. For example, some resources may be provisioned almost instantly, while others might take several minutes or longer depending on various factors such as the complexity of the resource or the current workload of the cloud provider.

In contrast, immediate execution implies that changes would show up in the cloud environment as soon as the apply command runs, which is not accurate because it does not account for the time needed for the provider to process these requests. Manual approvals do not normally occur in standard deployment processes for infrastructure as code in Terraform, as the apply command is generally automated. Lastly, thinking that changes would only reflect after a scheduled run does not align with how Terraform's apply function operates, as it performs actions on demand rather than on a schedule.