What does the upper case of the refreshment center have?

The upper case of the refreshment center is designed to maximize accessibility and organization of items needed during service. The inclusion of sliding doors allows for easy access to the contents while helping to maintain temperature control for the items stored inside. Shelves provide an organized way to store beverages and snacks, ensuring that flight attendants can quickly find and serve refreshments to passengers as needed. This design feature is practical for inflight service, facilitating an efficient workflow.

Other options might include components relevant to a refreshment center, but they do not fully encapsulate the design and functional aspects of the upper case, such as the sliding doors and shelves that enhance accessibility and organization.