A developer must run geographic load tests for an API across multiple AWS Regions and wants to deploy the required resources in each Region without changing the application code. Which approach meets this requirement?

AWS CloudFormation StackSets allow you to provision a common set of AWS resources across multiple AWS accounts and Regions with a single operation. This directly addresses the requirement to deploy resources in each Region without changing application code. The create-stack-set command automates the deployment of the CloudFormation template to the specified target Regions. Deploying a Lambda function in each Region to create stacks is overly complex and less efficient than StackSets for this use case. Authoring an AWS Systems Manager document is primarily for operational tasks and automation within instances, not for provisioning infrastructure across multiple Regions as effectively as CloudFormation StackSets. Running aws cli deploy for each Region would require individual commands for every Region, which is less automated and scalable than a single StackSet operation.