What item determines which diner will be served first?

The item that determines which diner will be served first is the "buck." In a formal dining setting, a "buck" refers to a system used in food service where a specific item, such as a small marker or token, is placed at each diner’s seat or used in conjunction with a seating arrangement. This system helps servers identify the order in which diners should be served, ensuring that the service is organized and efficient. By using a buck, servers can easily track whose meal is ready to be served next, which is particularly important in managing meal service at large events or formal dinners where timing and order are crucial.

In contrast, a dinner plate, silverware, and tablecloth do not contribute to the serving order. While these items are essential for dining, they serve different purposes: providing the means to eat, establishing a dining setting, or presenting the meal and ambiance. However, they don't play a role in determining the sequence of service among diners.