A child module is an encapsulated and reusable component. It cannot directly access variables, local values, or data sources from its parent module's scope. For a child module to use a value from its parent, the parent module must explicitly pass that value to an input variable defined within the child module. This design principle ensures that modules are self-contained and predictable, preventing them from being implicitly affected by the environment in which they are called.

A. True: This is incorrect. It violates Terraform's fundamental principle of module encapsulation. Direct access is not permitted; variables must be explicitly passed as arguments.

1. HashiCorp Terraform Documentation. (n.d.). Module Composition. In Terraform Language. Retrieved from https://developer.hashicorp.com/terraform/language/modules/compose. The section "Child Module Encapsulation" explicitly states: "A child module can't access the variables of a parent module

but a parent module can pass values to the input variables of a child module."

2. HashiCorp Terraform Documentation. (n.d.). Calling a Child Module. In Terraform Language. Retrieved from https://developer.hashicorp.com/terraform/language/modules/syntax#calling-a-child-module. This section demonstrates that values are passed to a module as arguments within the module block

reinforcing the concept of explicit passing rather than direct access.

3. HashiCorp Terraform Documentation. (n.d.). Input Variables. In Terraform Language. Retrieved from https://developer.hashicorp.com/terraform/language/values/variables. The documentation describes input variables as the formal parameters for a module

which is the mechanism for passing data into it.