Changing the Terraform backend from the default "local" backend to a different one after doing your first terraform apply is:
Changing the Terraform backend from the default "local" backend to a different one after doing your first terraform apply is:
Changing the Terraform backend from the default 'local' backend to a different one after doing your first terraform apply is optional. While it may be necessary to re-run some commands such as 'terraform init' to validate and configure the new backend, the act of changing the backend itself is not impossible nor mandatory. It depends on the requirements of your specific use case.
You can do it. Not a must. If it's useful epends on the usecase. So B.
It is optional
It is Optional - so it's B
its gotta be C as there will be an error. When you change a backend's configuration, you must run terraform init again to validate and configure the backend before you can perform any plans, applies, or state operations.
This has nothing to do with the question. Can you change the backend after running your first `terraform apply`? Yes, you can. Sure you'll have to run the init again but that's another story - question doesn't mention anything about "after".
B. Optional , the mandatory using terraform init
I think most of you misread the question. It is not about requirement of running terraform apply it is about whether it is possible to change backend after first apply command.
SO WHAT IS THE ANSWER ?