A company runs an application on EC2 instances that need access to RDS credentials stored...

Create an IAM role, and attach the role to each EC2 instance profile. Use an identity-based policy to grant the role access to the secret.

Create an IAM user, and attach the user to each EC2 instance profile. Use a resource-based policy to grant the user access to the secret.

Create a resource-based policy for the secret. Use EC2 Instance Connect to access the secret.

Create an identity-based policy for the secret. Grant direct access to the EC2 instances.