Toppings are add-ons you would check on or off (yes / no). For example, on sandwich you may have toppings such as lettuce, tomatoes, onions, etc. So a customer would check the box indicating they want those particular add-ons. There is no cost associated with toppings.
Options are add-ons that you would select one from a set of choices. For example, on a sandwich you may have an Option called "Bread". Under that Option would be the choices of White, Wheat, Sourdough and Ciabatta. The customer can only choose one of those from a drop-down list. Options may or may not have a cost associated with them. For example, the White, Wheat and Sourdough are included but the Ciabatta costs $0.50 extra.
Extras are add-ons that are check on or off (yes /no) which always have a cost associated with them. For example, a sandwhich may have extras such as "Add Bacon" for $0.50 or "Add Chips" for $1.50.
Note: You can change the labels for "Toppings", "Options", and "Extras" to be whatever you want too.