To ensure that each team's service account has the necessary permissions to manage resources within their assigned folders while adhering to the principle of least privilege, the following considerations apply:​

Folder Administrator Role: Granting each service account the Folder Administrator role on its respective folder provides comprehensive permissions to manage resources within that folder, including creating, updating, and deleting projects and resources. This approach ensures that teams have the necessary control over their environments without extending permissions beyond their assigned scope.​

Principle of Least Privilege: By assigning permissions at the folder level, you limit the service account's access to only the resources within its designated folder, aligning with the principle of least privilege and reducing the risk of unauthorized access to other parts of the organization.​

Therefore, Option A is the most effective approach, as it provides the necessary permissions for teams to manage their resources within their assigned folders while adhering to security best practices.​