The correct answer is D. The healthier lunch is more expensive because it uses better-quality ingredients.
The quality of the products determines the price, the higher the quality, the higher the price to be paid. And in the case of healthy menus, the raw material with which they are made is of better quality than that used in average menus.
For this reason, it is logical that healthy menus have a higher cost than other menus. The concept of healthy requires a superior treatment of raw materials, which generates an extra cost that is transferred to the consumer.