https://aws.amazon.com/about-aws/whats-new/2016/09/aws-codedeploy-introduces-deployment-monitoring-with-amazon-cloudwatch-alarms-and-automatic-deployment-rollback/

https://aws.amazon.com/blogs/mt/org-aggregator-delegated-admin/ https://docs.aws.amazon.com/organizations/latest/userguide/services-that-can-integrate-config.html

To implement governance controls that restrict AWS service usage to within the United States and ensure alerts for any activity outside the governance policy, the following actions will meet the requirements:
A) Create an AWS Organizations SCP that denies access to all non-global services in non-US Regions. Attach the policy to the root of the organization. This action will effectively prevent users and roles in all accounts within the organization from accessing services in non-US Regions12.
B) Configure AWS CloudTrail to send logs to Amazon CloudWatch Logs and enable it for all Regions. Use a CloudWatch Logs metric filter to send an alert on any service activity in non-US Regions. This action will allow monitoring of all AWS Regions and will trigger alerts if any activity is detected in non-US Regions, ensuring that the governance team is notified as soon as possible3.
Reference:
AWS Documentation on Service Control Policies (SCPs) and how they can be used to manage permissions and restrict access based on Regions12.
AWS Documentation on monitoring CloudTrail log files with Amazon CloudWatch Logs to set up alerts for specific activities3.

You need to understand how SCP inheritance works in AWS. The way it works for Deny policies is different that allow policies.
Allow polices are passing down to children ONLY if they don't have an allow policy.
Deny policies always pass down to children.
That's why there is always an SCP set to the Root to allow everything by default. If you limit this policy, the whole organization will be limited, not matter what other policies are saying for the other OUs. So it's not A. It's not D because it restricts the wrong OU.

The requirement is to create the infrastructure as code (IaC) and the CI/CD pipeline for the Lambda application that uses canary deployment and automated rollback. To do this, the DevOps team needs to use the following steps:
Create an AWS Serverless Application Model (AWS SAM) template for the application. AWS SAM is a framework that simplifies the development and deployment of serverless applications on AWS. AWS SAM allows customers to define Lambda functions and other resources in a template by using a simplified syntax. For each Lambda function, the DevOps team can include configurations for the AutoPublishAlias property and the DeploymentPreference property. The AutoPublishAlias property specifies the name of the alias that points to the latest version of the function. The DeploymentPreference property specifies how CodeDeploy deploys new versions of the function. By configuring the deployment configuration type to LambdaCanary10Percent10Minutes, the DevOps team can enable canary deployment with 10% of traffic shifted to the new version every 10 minutes.
Create an AWS CodeCommit repository. Create an AWS CodePipeline pipeline. Use the CodeCommit repository in a new source stage that starts the pipeline. Create an AWS CodeBuild project to deploy the AWS SAM template. CodeCommit is a fully managed source control service that hosts Git repositories. CodePipeline is a fully managed continuous delivery service that automates the release process of software applications. CodeBuild is a fully managed continuous integration service that compiles source code and runs tests. By using these services, the DevOps team can create a CI/CD pipeline for the Lambda application. The pipeline should use the CodeCommit repository as the source stage, where the DevOps team can upload the SAM template and source code. The pipeline should also use a CodeBuild project as the build stage, where the SAM template can be built and deployed.
Create an Amazon CloudWatch alarm for each Lambda function. Configure the alarms to enter the ALARM state if any errors are detected. Configure an evaluation period, dimensions for each Lambda function and version, and the namespace as AWS/Lambda on the Errors metric. CloudWatch is a service that monitors and collects metrics from AWS resources and applications. CloudWatch alarms are actions that are triggered when a metric crosses a specified threshold. By creating CloudWatch alarms for each Lambda function, the DevOps team can monitor the health and performance of each function version during deployment. By configuring the alarms to enter the ALARM state if any errors are detected, the DevOps team can enable automated rollback if any failures are reported.