Which AWS services should be used to enable this access?

Explanations:

AWS Directory Service is primarily used for managing directories and integrating with Microsoft Active Directory. It is not directly related to controlling access to S3 buckets.

AWS Shield provides protection against DDoS attacks, but it does not manage secure access to resources like S3 buckets.

IAM roles allow users to assume permissions to access specific resources, such as Amazon S3, in a secure manner. This is necessary for controlling who can access the content stored in an S3 bucket.

Amazon Cognito helps manage user authentication and authorization for mobile applications, enabling users to securely access their content stored in a shared S3 bucket.

AWS Organizations is used for managing multiple AWS accounts, but it does not provide direct user authentication or secure access to individual resources like S3 buckets.