Within the food service industry (restaurants that serve meals to customers, but not just fast food), find examples of firms that have sustained competitive advantage by competing on the basis of (1) cost leadership, (2) response, and (3) differentiation.
Cite one example in each category; provide a sentence or two in support of each choice. Do not use fast-food chains for all categories.
(Hint: A "99¢ menu" is very easily copied and is not a good source of sustained advantage.)