Which type of changes affect a quick-serve restaurant's sales forecast and can be categorized as internal changes?

The correct answer is operational changes, as these refer to adjustments made within the restaurant that can significantly impact its sales forecast. Internal changes encompass aspects such as menu adjustments, alterations in service speed or efficiency, staffing changes, and modifications in pricing strategies. These operational factors can affect customer experience, operational efficiency, and ultimately sales volume.

For instance, if a restaurant revamps its menu to introduce new items that align better with customer tastes, it is likely to attract more customers or encourage existing customers to purchase additional items, thus impacting sales positively. Similarly, operational changes that improve service speed or efficiency can increase the volume of customers served, leading to higher sales.

Market changes and external market shifts, while important, fall outside of the internal realm, as they deal with broader influences like economic conditions or competitor actions that are not directly controllable by the restaurant. Customer demographic changes also reflect external factors that relate to the population of customers and their preferences rather than changes made within the restaurant.