Which of the following is the best description of an internal service?

The best description of an internal service is a service delivered between departments in the same organization. Internal services facilitate operations within an organization, supporting various departments to function effectively and efficiently. By delivering these services, one department can enable another to achieve its goals without interacting with external customers.

In ITIL, understanding the distinction between internal and external services is crucial for managing services effectively. Internal services typically focus on improving collaboration, productivity, and resource utilization within the organization. They can include services like IT support, HR services, or any function that helps an internal team operate smoothly.

The other choices describe different types of services that do not fit the definition of an internal service. For instance, a service providing value while transferring risk and cost to the customer points to an external service model. A service delivered to customers outside the organization is clearly external and focuses on customer-facing interactions. Lastly, a service that is not directly used by the business but is necessary for providing overall service may describe a support service or component, but it does not capture the essence of what constitutes an internal service.