Which of the following best describes "Extras" on the menu?

The choice of "Additional toppings or sides that can be added" accurately reflects the concept of "Extras" on the menu. In the context of a fast-food establishment like Jack in the Box, "Extras" typically refer to optional additions that enhance the meal. This can include toppings such as extra cheese, bacon, or vegetables, as well as side items like fries or onion rings that can be requested alongside a main offering.

These additions allow customers to customize their orders according to their preferences, creating a more personalized dining experience. The other choices present different aspects of the menu; however, they do not encapsulate the full range of what "Extras" encompasses. For instance, items that come with every meal don’t represent optional additions, while desserts and beverages are specific categories rather than customizable enhancements. This distinction is what makes the correct answer relevant in the context of menu offerings at Jack in the Box.