Detailed Explanation:
Rationale for Correct Answer: The import block declaratively tells Terraform to associate an existing infrastructure object with a Terraform resource address. After the configuration is applied, Terraform imports the existing resource and updates Terraform state so that Terraform can manage it.
Analysis of Incorrect Options (Distractors):
A: Moving resources between state addresses or state files is a state-management operation; it is not the purpose of an import block.
B: The import block does not merge Terraform state files.
C: Modules are downloaded during initialization, not by an import block.
Key Concept: Bringing existing infrastructure under Terraform management by importing it into state.
Reference: Terraform Objective - Implement and Maintain State; HashiCorp Terraform documentation:
Import existing resources.