What type of document defines permissions for IAM users or groups?

The correct answer is JSON Policies because these documents explicitly define permissions associated with AWS Identity and Access Management (IAM) users or groups. JSON (JavaScript Object Notation) is the format utilized to create policies that specify what actions are allowed or denied on specific resources within AWS.

JSON Policies consist of statements that identify the permitted actions (like s3:PutObject for uploading files to an S3 bucket), the resources that the actions apply to, and any conditions that must be met for those permissions to be applicable. This structured approach enables fine-grained control over access permissions, allowing administrators to define who can access what within an AWS environment securely.

Access Keys, on the other hand, are used to authenticate an IAM user or role to make API requests but do not define specific permissions. Connection Strings are typically associated with database connections and do not relate to IAM permissions, while Audit Reports are outputs of security assessments but do not define permissions.