Which AWS service or feature should the developer use to provide these credentials?

Explanations:

IAM policies define permissions for users and groups but do not provide temporary security credentials. They are used to manage access to AWS resources rather than generate temporary credentials.

IAM user groups are used to manage IAM users and their permissions collectively, but they do not offer temporary security credentials. They serve as a way to simplify permission management for multiple users.

AWS Security Token Service (AWS STS) is specifically designed to provide temporary security credentials for AWS users and services. It allows users to request temporary credentials that grant access to AWS resources for a limited duration.

AWS IAM Identity Center (formerly AWS Single Sign-On) is a service that allows users to manage access to AWS accounts and applications, but it does not directly issue temporary security credentials. Instead, it provides a way to manage user identities and access across AWS accounts.