A company runs applications on Amazon EC2 instances that connect to Amazon RDS databases using an IAM role with associated policies. The company wants to use AWS Systems Manager to patch the EC2 instances without disrupting the running applications. Which solution meets these requirements?

Enabling Default Host Configuration Management in Systems Manager automatically configures EC2 instances to be managed by Systems Manager. This includes attaching the necessary IAM permissions (like AmazonSSMManagedInstanceCore) to the instance's existing IAM role, allowing Systems Manager to perform actions like patching without requiring manual IAM role modifications or disrupting applications. Creating a new IAM role and attaching it to the instances alongside the existing role is not the most efficient solution and could lead to permission conflicts or complexity. Creating an IAM user for Systems Manager is incorrect because Systems Manager uses instance profiles (IAM roles attached to instances), not IAM users, for EC2 management. Removing existing policies from the current IAM role would break the application's connectivity to RDS, which is unacceptable.