Your fleet of Amazon Linux EC2 instances is managed with AWS Systems Manager; SSM Agent is installed and all instances use IMDSv2. Company policy requires developers to use only Amazon Linux. You need all newly created EC2 instances to be automatically managed by Systems Manager with the most operational efficiency. Which solution accomplishes this?

The correct solution leverages the default-ec2-instance-management-role setting in Systems Manager. This setting automatically assigns the specified IAM instance profile to new EC2 instances launched without one, ensuring they are immediately manageable by SSM. The AmazonSSMManagedEC2InstanceDefaultPolicy provides the necessary permissions for SSM Agent to communicate with the Systems Manager service. Incorrect options: Enabling AWS Config with a rule to check for SSM Agent installation and automatic remediation is reactive, not proactive. Instances would be created without SSM management initially, then remediated, which is less efficient than automatic management from creation. Systems Manager Patch Manager is designed for patching operating systems and applications, not for installing SSM Agent on new instances as a primary management solution. It's an indirect and less efficient approach for initial agent installation. Creating an EC2 instance role and using AWS Config with ec2-instance-profile-attached rule and automatic remediation is also a reactive approach. It relies on detecting a missing role and then remediating, which introduces a delay and additional complexity compared to the proactive default setting.