Explanation

To use the AWS CLI (Command Line Interface), developers need AWS access keys which consist of:

• Access Key ID
• Secret Access Key

These credentials are required for programmatic access to AWS services through the CLI, SDKs, and APIs.

Why the other options are incorrect:

• User name and password: Used for AWS Management Console login, not CLI access
• AWS Systems Manager: A management service for operational data and automation, not for CLI authentication
• Root password access: Root credentials provide full account access but are not the recommended method for CLI usage; IAM users with access keys are the secure approach

Best Practice:

• Create IAM users with appropriate permissions
• Generate access keys for those users
• Use these access keys to configure the AWS CLI
• Never use root credentials for daily operations