An application running on Amazon EC2 needs login credentials to access a database. The login credentials are stored in AWS Systems Manager Parameter Store as secure string parameters.
What is the MOST secure way to grant the application access to the credentials?

A. Create an IAM EC2 role for the EC2 instances and grant the role permission to read the Systems Manager parameters
B. Create an IAM group for the application and grant the group permissions to read the Systems Manager parameters
C. Create an IAM policy for the application and grant the policy permission to read the Systems Manager parameters
D. Create an IAM user for the application and grant the user permission to read the Systems Manager parameters