CloudFormation StackSets are designed specifically to deploy and manage the same CloudFormation stack across multiple AWS accounts and Regions from a centralized administration point. When accounts are managed under AWS Organizations, StackSets can integrate directly with Organizations to target Organizational Units (OUs) or specific accounts, which minimizes operational overhead. This removes the need to manually assume roles and deploy stacks one-by-one, and avoids building custom automation (Lambda + cross-account role assumption + account enumeration + error handling + retries + idempotency).

With StackSets, you define the template once and then create stack instances across many accounts in a controlled and consistent manner. StackSets provide built-in features for: (1) centralized rollout and updates, (2) drift detection, (3) automatic deployment to new accounts (when using Organizations integration), and (4) standardized execution roles. This is operationally simpler and safer than scripting because StackSets handle orchestration and track deployment state per account/Region.

Option A increases manual work and is error-prone at scale. Options B and C require custom Lambda orchestration, cross-account permissions, and ongoing maintenance for failure modes and change management. StackSets provide the native “least ops” approach to multi-account CloudFormation deployments under Organizations.