A solutions architect is deploying a new security tool into several AWS Regions that were not previously used. The deployment uses an AWS CloudFormation stack set. The stack set's template defines an IAM role that uses a custom (explicit) name. After creating the stack set, none of the stack instances are created successfully. What should the solutions architect do so the stacks can be deployed successfully?

The correct answer addresses two critical issues. First, new AWS Regions are opt-in by default for many accounts, so they must be explicitly enabled before any resources can be deployed there. Second, CloudFormation requires explicit acknowledgment when creating IAM resources with custom names due to their potential to alter permissions. The CAPABILITYNAMEDIAM capability provides this acknowledgment. Incorrect options: Requesting a quota increase for CloudFormation stacks is unlikely to be the issue, as the stack set creation itself failed, not just a specific stack limit. CAPABILITYIAM is used for IAM resources without custom names, which isn't the case here. Choosing the SELFMANAGED permissions model is about how permissions are handled, not about enabling regions or acknowledging IAM resource creation. Providing an administration role ARN is part of setting up stack set permissions, but it doesn't address the need to enable new regions or acknowledge the creation of named IAM resources.